Lessons Learned

3/7/08 1:10:56 PM 3/7/08 1:10:56 PM 4/6/08 2:45:28 PM /08 2:45:28PM 4/6 3/7/08 1:10:56 PM PROCEEDINGS The Getty Institute The Conservation Lessons Learned: Learned: Lessons Reflecting Theory the on and Practice Mosaic of Conservation The 9th Conference of the International the International of 9th Conference The of the Conservation for Committee Tunisia, Hammamet, Mosaics, 29–DecemberNovember 3, 2005

PROCEEDINGS Lessons Learned: Reflecting on the Theory and Practice of Mosaic Conservation ISBN 978-0-89236-920-1 Printed in China Printed Getty Publications 800-223-3431 www.getty.edu/publications The Getty Conservation Institute Getty Conservation The Angeles Los TJ272-12 Cover 200L CTP 1 Untitled-2.indd 1Untitled 2 indd 1 TJ272-12 Cover 200L CTP 1 TJ272-12 Cover 200L CTP 1 Black

Lessons Learned: Refl ecting on the Theory and Practice of Mosaic Conservation Leçons retenues : Les enseignements tirés des expériences passées dans le domaine de la conservation des mosaïques TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” i TJ14-3 P i-006 200L CTP.indd i 3/3/08 10:47:25 AM i Black

Lessons Learned: Refl ecting on the Theory and Practice of Mosaic Conservation Leçons retenues : Les enseignements tirés des expériences passées dans le domaine de la conservation des mosaïques

Proceedings of the 9th ICCM Conference Hammamet, Tunisia, November 29–December 3, 2005

Actes de la 9e Conférence de l’ICCM Hammamet, Tunisie, 29 novembre–3 décembre 2005

Edited by Aïcha Ben Abed, Martha Demas, and Th omas Roby Publié sous la direction d’Aïcha Ben Abed, Martha Demas et Th omas Roby

The Getty Conservation Institute Los Angeles TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” iii TJ14-3 P i-006 200L CTP.indd iii 3/3/08 10:47:26 AM Cyan Magenta Yellow Black

The Getty Conservation Institute

Timothy P. Whalen, Director Institut National du Patrimoine Jeanne Marie Teutonico, Associate Director, Programs

The Getty Conservation Institute works internationally to advance conservation and to enhance and encourage the preservation and understanding of the visual arts in all The Getty Conservation Institute of their dimensions—objects, collections, architecture, and sites. The Institute serves the conservation community through scientific research; education and training; field projects; and the dissemination of the results of both its work and the work of others in the field. In all its endeavors, the Institute is committed to addressing unanswered questions and promoting the highest possible standards of conservation practice. The 9th ICCM Conference was co-organized by the Institut National du Patrimoine, Tunisia, the Getty Publications Getty Conservation Institute, and the International 1200 Getty Center Drive, Suite 500 Committee for the Conservation of Mosaics, with the Los Angeles, California 90049-1682 support of ICCROM and the University of Cyprus. www.getty.edu

Gregory Britton, Publisher Mark Greenberg, Editor in Chief Tevvy Ball, Editor Sheila Berg, Copy Editor (English) Sabine de Valence, Copy Editor (French) Pamela Heath, Production Coordinator Hespenheide Design, Designer Anne-Marie Driss, Translator

Printed and bound in China through Asia Pacific Offset, Inc. FRONT COVER: In situ conservation of a floor mosaic at Thuburbo Majus, Tunisia. Photo: Elsa Bourguignon.

Library of Congress Cataloging-in-Publication Data

International Committee for the Conservation of Mosaics. Conference (9th : 2005 : Hammamat, Tunisia)

TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) Lessons learned : reflecting on the theory and practice of mosaic conservation : proceedings of the 9th ICCM Conference, Hammamet, Tunisia, November 29– December 3, 2005 = Leçons retenues : les enseignements tirés des experiences passées dans le domaine de la conservation des mosaïques : actes de la 9ème conference de l’ICCM, Hammamet, Tunisie, 29 novembre–3 décembre 2005 / edited by Aïcha Ben Abed, Martha Demas, and Thomas Roby. p. cm. English and French. Includes bibliographical references. ISBN 978-0-89236-920-1 (pbk.) 1. Mosaics—Conservation and restoration—Congresses. I. Ben Khader, Aïcha Ben Abed. II. Demas, M. III. Roby, Thomas. IV. Getty Conservation Institute. V. Title. VI. Title: Leçons retenues. NA3752.5.I58 2005 738.5028'8—dc22 2007046195

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Contents

Timothy P. Whalen and Mohammed Béji Ben Mami xi Foreword xiii Avant-propos

Aïcha Ben Abed, Martha Demas, and Thomas Roby xv Acknowledgments xvi Remerciements

Demetrios Michaelides xvii Opening Remarks of the President of the ICCM on the Occasion of the 9th Conference xix Allocution d’ouverture du Président de l’ICCM à l’occasion de la 9e Conference

Aïcha Ben Abed, Martha Demas, and Thomas Roby 1 Introduction 3 Introduction

PART ONE Evaluating Mosaic Practice

Gaël de Guichen and Roberto Nardi 9 Mosaic Conservation: Fifty Years of Modern Practice

Martha Demas, Thomas Roby, Neville Agnew, 15 Learning from Past Interventions: Evaluation of the Project to Giorgio Capriotti, Niki Savvides, Conserve the Orpheus Mosaic at Paphos, Cyprus and Demetrios Michaelides

Évelyne Chantriaux, Marion Hayes, Christophe 26 Bilan d’opérations réalisées par l’Atelier de Saint-Romain- Laporte, Andréas Phoungas et Maurice Simon en-Gal

Francesca Piqué, Rachel Burch, Thomas Roby, 33 Learning from the Literature: A Review of Published Works and Martha Demas on Mosaic Deterioration and Conservation Treatments

Denis Weidmann 46 Orbe-Boscéaz (Canton de Vaud, Suisse) 1975–2005 : 30 ans de réflexions sur la conservation d’anciennes et de nouvelles mosaïques

Jarosław Dobrowolski 51 Villa of the Birds Five Years Later: Early Roman Mosaics in Alexandria, Egypt TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” v TJ14-3 P i-006 200L CTP.indd v 3/3/08 10:47:27 AM Black

Charalambos Bakirtzis, Pelagia Mastora, 57 Lessons Learned in Theory and Practice of Mosaic Styliani Vassiliadou, and Nikos Pitsalidis Treatments: The Case of the Wall Mosaics in the Church of the Holy Apostles, Thessaloniki, Greece

64 Discussion

PART TWO Caring for Mosaics in Museums

Maria de Fátima Abraços 69 Conservation et restauration des mosaïques romaines au Portugal – Quelques exemples dans les collections de musées

Carmen Dávila Buitrón et 75 Conservation d’un ensemble d’emblemata du Musée M. Antonia Moreno Cifuentes Archéologique National

Maja Frankovic 85 Inadequate Storage Conditions: Causes of Deterioration of Mosaics in a Museum Environment

Marie-Laure Courboulès, Abdelkader Bensalah, 91 Coopération algéro-française pour la préservation de Mouloud Derram et Mohamed Chérif Hamza collections anciennes de mosaïques des musées algériens

Robert (Chip) Vincent 100 Conservation and Display of Three Mosaics in the Greco- Roman Museum, Alexandria, Egypt

C. Mei-An Tsu, Pamela Hatchfield, 108 Where Theory Meets Practice: The Conservation and Christine Kondoleon, and Craig Barnes Presentation of a Roman Floor Mosaic at the Museum of Fine Arts, Boston

118 Discussion

PART THREE Documenting and Assessing Sites at Risk TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S)

Mustafa Şahin, Derya Şahin, 123 The Mosaic Corpus of Turkey: A New International David Parrish, and Werner Jobst Research Project

Fathi Bejaoui 126 La gestion des pavements de mosaïques découverts fortuitement : Déposer ou conserver in situ?

Hande Kökten 131 Mosaic Floors Unearthed at Rescue Excavations in Turkey: A Philosophical and Ethical Evaluation of the Decision- Making Process

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PART FOUR Managing Sites with Mosaics

Amr Nawar Al Muayyad Al-Azm 139 Conservation and Preservation of Mosaics in Syria: The Case for a Multidisciplinary Approach—or New Strategies for Old Problems

Mervat Ma’moun Ha’obsh 144 Um Er-Rasas (Um Al-Rasas): Preservation of the Mosaics at a New World Heritage Site in Jordan

Konstantinos L. Zachos 151 Conservation and Restoration of the Nikopolis Mosaics: A Program for Integrated Management and Presentation of the Archaeological Site

Hassan Limane et Gaetano Palumbo 160 Les mosaïques de Volubilis (Maroc) : Planification de la conservation et de la gestion

Chiara Zizola 165 The Legacy of Nora, Sardinia: A Project for the Conservation, Restoration, and Maintenance of Mosaics

174 Discussion

PART FIVE Sheltering Mosaics

John Stewart 181 Rapid Assessment of Shelters over Mosaics: Methodology and Initial Results from England

Jacques Neguer and Yael Alef 192 Rapid Assessment of Shelters over Mosaics: Initial Results from Israel

Sibylla Tringham and John Stewart 204 Protective Shelters over Archaeological Sites: A Review of Assessment Initiatives

Demetrios Michaelides and Niki Savvides 215 Lessons Not Learned: The Shelters at Kourion, Cyprus

Isabelle Skaf et Yasmine Makaroun Bou Assaf 224 Une nouvelle approche pour la préservation in situ des mosaïques et vestiges archéologiques au Liban : La crypte de l’église Saint-Georges à Beyrouth

Philip Bethell 230 140 Years of Mosaic Conservation at Chedworth Roman Villa, United Kingdom

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PART SIX Training of Conservation Practitioners

Patrick Blanc et Hani Najar 245 Questions d’actualité : La conservation des mosaïques dans le territoire de Gaza, formation de personnel et travaux d’intervention et de préservation des mosaïques in situ

Osama Hamdan, Tagrid Shaaban, and Carla Benelli 251 Experiences in Mosaic Conservation Training in the Middle East

Thomas Roby, Livia Alberti, Elsa Bourguignon, 258 Training of Technicians for the Maintenance of in Situ and Aïcha Ben Abed Mosaics: An Assessment of the Tunisian Initiative after Three Years

Aïcha Ben Abed 265 Une stratégie tunisienne pour conserver la mosaïque

268 Discussion

PART SEVEN Case Studies

Michele Macchiarola and Gianluigi Fiorella 273 The Study of Hydraulic Lime Mortars for the Conservation of Mosaics

José Lourenço Gonçalves 281 Reburial versus Sheltering: Experiments in Preventive Conservation of the Mosaics in the Roman Villa of Rabaçal, Penela, Portugal

Sabah Ferdi et Mohamed Chérif Hamza 289 Consolidation in situ de la mosaïque de la grande basilique de Tipasa, Algérie

Amina-Aïcha Malek et Marie-Laure Courboulès 294 Les mosaïques de Lambèse, Algérie TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) Patrick Blanc 303 La mosaïque de Grand (Vosges, France) : Un exemple ancien pour la conservation des vestiges archéologiques sur site

Kent Severson and Diane Fullick 312 Backing Roman Mosaics with Glass Fiber Reinforced Cement

320 Discussion

PART EIGHT Summary Conclusions and Recommendations

Jeanne Marie Teutonico and Roberto Nardi 327 Summary Conclusions and Recommendations/ Conclusions et recommendations

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PART NINE Posters

Panayota Assimakopopoulou-Atzaka, 335 Mosaic Icons in Greece: Techniques and Methods of Eleni Chrysafi, Christine Papakyriakou, Magda Conservation Parcharidou-Anagnostou, and Anastassia Pliota

Luc Long, Véronique Blanc-Bijon, Patrick Blanc 340 L’emblema découvert en mer, au large d’Agde : Technique de et Marie-Laure Courboulès fabrication – traitement de conservation

Évelyne Chantriaux, Marion Hayes, Christophe 344 La restauration de la mosaïque du VIe siècle de Qabr Laporte, Andréas Phoungas et Maurice Simon Hiram (Liban) par l’atelier de restauration de mosaïques de Saint-Romain-en-Gal

Abdelilah Dekayir, Marc Amouric, 348 Study of the Mineralogical and Chemical Characteristics Juan Olives, and Abdelkader Chergui of Materials Used in the Construction of Roman Mosaics in Volubilis, Morocco, with a View toward Their Conservation

Salvador Domínguez-Bella, Maria Luisa 354 The Lifting Procedure of the Bacchus Mosaic from the Millán Salgado, and Ana Durante Macias Roman Villa in Barrio Jarana, Cádiz, Spain

Işıl R. Işıklıkaya 358 Comparison of Conventional and Photogrammetric Documentation of Mosaics at the Agora of Perge

Laurence Krougly et J. M. Monraval 362 Un emblema provenant d’Utique conservé au Musée du Louvre

Ilaria Pennati, Carlo Lalli, Annamaria Giusti, 365 The Project for the Conservation, Maintenance, and Giancarlo Raddi delle Ruote, Giordana Benazzi, Utilization of the Pavement of the Cathedral in and Michele Macchiarola Spoleto, Italy

Aurélie Martin 369 Problématique posée par les réintégrations des lacunes dans la mosaïque des Monstres marins de Lambèse-Tazoult, Algérie

Ewa Parandowska 373 The Byzantine Painted Floor in Salamiya, Syria: Possibilities for Conservation and Presentation

Konstantinos D. Politis, 377 The Syrian Mosaic Pavement Documentation Training Amr Nawar Al Muayyad Al-Azm, Program and Charalambos Bakirtzis

Elyas Saffaran 380 Étude sur l’état de conservation des mosaïques du Musée National d’Iran à partir de vestiges du site archéologique sassanide de Bîchâpour TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” ix TJ14-3 P i-006 200L CTP.indd ix 3/3/08 10:47:28 AM Black

Cristina Boschetti, Anna Corradi, Bruno Fabbri, 385 Archaeometric Analysis and Weathering Effects on Cristina Leonelli, Michele Macchiarola, Pompeii’s Nymphaea Mosaics Andrea Ruffi ni, Sara Santoro, and Paolo Veronesi

Y. Selçuk Sener 389 An Assessment of Recent in Situ Conservation Treatments of Mosaics in Turkey

Füsun Tülek 393 An Evaluation of the Preservation of Reburied Mosaics in Cilicia

Şehrigül Yeşil Erdek 397 The Lifting of a Mosaic from the Site of Letoon and Its Replacement with a Replica

403 Authors/Auteurs

413 List of Conference Participants/Liste des participants à la conférence TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S)

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Foreword

he triennial conferences of the International Committee on behalf of the ICCM. As a result of this participation, two for the Conservation of Mosaics (ICCM) have been an members from Arabic-speaking countries were elected to the Tessential source of information for professionals about board of the ICCM at the end of the conference. Although the mosaic conservation since the ICCM’s founding in 1977. We are languages in offi cial use during the conference were limited to pleased to augment this distinguished tradition with the publi- French and English, an Arabic translation of the abstracts was cation of the proceedings of the 9th ICCM Conference, held in made available by ICCROM through the support of its director- Hammamet, Tunisia, November 29–December 3, 2005. general, Nicholas Stanley-Price. Th e 9th ICCM Conference was co-organized by the Th e fruitful partnership among the organizers of the 9th Institut National du Patrimoine (INP) of Tunisia and the Getty conference builds on many years of cooperation. Th e GCI and Conservation Institute (GCI), with the support of ICCROM the INP have long collaborated to promote the conservation of (International Centre for the Study of the Preservation and ancient mosaics through training, documentation, and pub- Restoration of Cultural Property) and the University of Cyprus. lication initiatives. Th e INP hosted the second meeting of the Th e theme of the conference was “Lessons Learned: Refl ecting ICCM, in 1978, and under the leadership of the ICCM’s presi- on the Th eory and Practice of Mosaic Conservation,” and the dent since 1996, Demetrios Michaelides, the GCI partnered four-day program included more than sixty papers and post- with the University of Cyprus on the 6th ICCM Conference, ers by professionals in the conservation of ancient mosaics held in Nicosia, Cyprus, in 1996. Th e INP and the GCI owe spe- and art historians and archaeologists of the Roman world. cial gratitude to Dr. Michaelides, Aïcha Ben Abed, and Jeanne Th e organization of the conference in Tunisia was supported Marie Teutonico for their support of the partnership and their by His Excellency Mohamed El Aziz Ben Achour, Minister active engagement in the organization of the 9th Conference. of Culture, and facilitated by the Agence de Mise en Valeur An enriching complement to the conference sessions was du Patrimoine et de Promotion Culturelle (National Agency a program of visits to mosaic sites in Tunisia organized by the for the Promotion of Cultural Patrimony) and the National INP. Th ese visits allowed participants to see the sites fi rsthand Tourism Offi ce. and to confront the many realities of conserving and managing Th e location of the conference, in Tunisia, provided an mosaics in diff erent cultural, environmental, and social con- opportunity to attract participants from countries in the Middle texts. Th e participants visited the sites of Th uburbo Majus, Jebel East and North Africa, places that are rich in mosaic heritage Oust, Neapolis, and Carthage and attended a magnifi cent recep- but whose professionals have not been well represented at tion at the Bardo Museum in Tunis, which houses the world’s ICCM conferences. To make the most of this opportunity, the largest collection of ancient mosaics. At Th uburbo Majus, Jebel Getty Foundation awarded the ICCM a grant that enabled the Oust, and Neapolis participants were able to meet and view participation of forty-nine professionals from these regions. the work of the mosaic maintenance technicians (undergoing We are grateful to the University of Cyprus, through the good training in Tunisia by the INP and the GCI). Th e new regional offi ces of Demetrios Michaelides, for administering the grant archaeological museum in Nabeul off ered the opportunity to

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view the splendid fi gurative mosaics, which had been removed come to characterize mosaic conservation. We express our from the site many years ago following its excavation. gratitude to the volume editors for shepherding these proceed- Th e conference ended with an optional three-day tour of ings through to publication. mosaic sites in Libya, which was an exceptional opportunity to experience the scale and extraordinary artistic and his- Timothy P. Whalen toric signifi cance of Libya’s archaeological heritage. Th e tour Director included visits to the Archaeological Museum in Tripoli and Th e Getty Conservation Institute the ancient cities of Sabratha and Leptis Magna, as well as to Villa Silene and other sites normally closed to the public. We Mohammed Béji Ben Mami are grateful to Dr. Giuma Anag, director of Libya’s Department Director-General of Antiquities, for facilitating access to these sites. Institut National du Patrimoine, Tunisia Th e proceedings of the 9th ICCM Conference refl ect the breadth and diversity of issues and perspectives that have TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S)

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Avant-propos

es conférences triennales du Comité International pour quarante-neuf professionnels provenant de ces régions. Nous la Conservation des Mosaïques (ICCM) constituent, sommes reconnaissants à l’Université de Chypre, et particu- Ldepuis la création de l’ICCM, en 1977, une source essen- lièrement à Demetrios Michaelides, d’avoir bien voulu gérer tielle d’information pour les professionnels sur la conservation cette subvention au nom de l’ICCM. Cette participation a eu des mosaïques. C’est avec satisfaction que nous poursuivons pour résultat l’élection de deux membres provenant de pays cette tradition bien établie en y ajoutant la publication des arabophones au bureau de l’ICCM à la fi n de la conférence. actes de la 9e Conférence de l’ICCM, tenue à Hammamet, en Si les langues de la conférence ont été limitées au français et Tunisie, du 29 novembre au 3 décembre 2005. à l’anglais, une traduction en arabe des résumés à été prise La 9e Conférence a été organisée conjointement par l’In- en charge par l’ICCROM grâce au soutien de son Directeur stitut National du Patrimoine (INP) de Tunisie et l’Institut général, Nicholas Stanley-Price. Getty de Conservation (GCI) avec le soutien de l’ICCROM Le partenariat fructueux entre les organisateurs de la (Centre International d’Études pour la Conservation et la 9e Conférence repose sur plusieurs années de coopération. Restauration des Biens Culturels) et de l’Université de Chypre. Le GCI et l’INP collaborent depuis de nombreuses années La conférence a eu pour thème « Leçons retenues : Les en- pour promouvoir la conservation des mosaïques anciennes à seignements tirés des expériences passées dans le domaine de travers des initiatives de formation, de documentation et de la conservation des mosaïques » et le programme de quatre publication. L’INP a accueilli la deuxième réunion de l’ICCM jours comprenait plus de soixante communications et posters en 1978 et, sous la direction du président de l’ICCM depuis présentés par des professionnels du domaine de la conservation 1993, Demetrios Michaelides, le GCI a organisé en partenariat des mosaïques anciennes ainsi que des historiens de l’art et des avec l’Université de Chypre la 6e Conférence de l’ICCM à archéologues du monde romain. Son Excellence Mohamed Nicosie, Chypre, en 1996. L’INP et le GCI sont particulière- El Aziz Ben Achour, Ministre de la Culture, a accordé son ment reconnaissants au Dr Michaelides, Aïcha Ben Abed et soutien à l’organisation de la conférence en Tunisie et celle-ci Jeanne Marie Teutonico pour le soutien qu’ils ont apporté à a été facilitée par l’Agence de Mise en Valeur du Patrimoine et ce partenariat et pour leur engagement actif dans l’organisa- de la Promotion Culturelle ainsi que par l’Offi ce National du tion de la 9e Conférence. Tourisme. Les sessions de la conférence ont été enrichies par un La tenue de la conférence en Tunisie a été l’occasion programme de visites aux sites comportant des mosaïques, d’encourager la participation des pays du Moyen-Orient et organisé par l’INP. Ces visites ont permis aux participants de d’Afrique du Nord, des régions qui possèdent un riche patri- prendre connaissance des sites et de constater personnellement moine culturel mais dont les professionnels n’ont pas été les multiples réalités de la conservation et de la gestion des suffi samment représentés aux conférences de l’ICCM. Afi n mosaïques dans des contextes culturels, environnementaux d’optimiser cette opportunité, la Fondation Getty a accordé et sociaux diff érents. Des visites ont été organisées aux sites une subvention à l’ICCM qui a permis la participation de de Th uburbo Maius, Jebel Oust, Neapolis et Carthage et les

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participants ont assisté à une magnifi que réception au Musée sommes reconnaissants au Dr Giuma Anag, directeur du du Bardo de Tunis, qui renferme la plus grande collection Département des Antiquités de Libye, pour nous avoir facilité de mosaïques anciennes au monde. A Th uburbo Maius, Jebel l’accès à ces sites. Oust et Neapolis, les participants ont pu rencontrer et observer Les Actes de la 9e Conférence de l’ICCM refl ètent l’éten- le travail des techniciens d’entretien des mosaïques (formés en due et la diversité de la problématique et des perspectives qui Tunisie par l’INP et le GCI). Le nouveau Musée archéologi- désormais caractérisent la conservation des mosaïques. Nous que régional à Nabeul a permis aux participants de découvrir exprimons nos remerciements aux rédacteurs de ce volume les magnifi ques mosaïques fi gurées qui avaient été transférées pour avoir mené à bien la publication de ces actes. hors du site après les fouilles il y a de nombreuses années. La conférence s’est achevée avec une visite facultative Timothy P. Whalen de trois jours en Libye. Cette visite a constitué une occasion Directeur unique de constater l’ampleur et l’importance artistique et Institut Getty de Conservation historique du patrimoine archéologique libyen. Ce tour comprenait des visites au Musée archéologique à Tripoli, aux Mohammed Béji Ben Mami cités antiques de Sabratha et Leptis Magna, ainsi qu’à la Villa Directeur général Silène et autres sites normalement fermés au public. Nous Institut National du Patrimoine de Tunisie TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S)

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Acknowledgments

he successful organization of the 9th ICCM Conference Yedder, and Mourad Boulares expertly facilitated communica- and the publication of the proceedings were the result tion between French and English. Elsa Bourguignon, Sibylla Tof the eff orts and dedication of many individuals. In the Tringham, Niki Savvides, and Kenza Kahrim acted as session planning stage, the ICCM Scientifi c Committee of the Board rapporteurs and provided summary points for inclusion in the (Demetrios Michaelides, Jeanne Marie Teutonico, Roberto fi nal presentation. Nardi, Évelyne Chantriaux, and John Stewart) provided their Kathleen Louw and Cynthia Godlewski undertook coor- time and expertise in conceptualizing the themes of the con- dination of the proceedings for the GCI, and Tevvy Ball and ference and selecting papers. Pamela Heath managed the project and coordinated produc- In Tunisia, through the support of the INP’s director, tion, respectively, for Getty Publications. Gary Hespenheide Mohammed Béji Ben Mami, INP staff Saloua Zangar, Fathi guided the design of the book. Elsa Bourguignon assisted Bejaoui, Habib Ben Younes, Tahar Ghalia, Mounir Fantar, and with editing the discussion transcripts. Preliminary editing Féthi Chelbi took an active role in the conference arrange- of papers was done by Anne Kurashige; fi nal copyediting of ments and visits to mosaic sites and museums. Archaeologist the entire proceedings volume was undertaken by Sheila Berg Jean-Pierre Darmon provided his insights, acquired through (English) and Sabine de Valence (French). Th e summaries many years of experience, during site visits. INP mosaic main- and introductory material were translated from English and tenance technicians also contributed to the site visits by dem- French by Anne-Marie Driss. onstrating techniques and results of their mosaic work. On behalf of the GCI and the INP, we express our sin- Kathleen Louw (GCI) skillfully took on the onerous task cere thanks to all these individuals for their contributions to of coordinating the conference arrangements and the postcon- bringing the conference and its publication to a rewarding ference tour. She was ably assisted in the preparatory stages completion. by Niki Savvides on behalf of the ICCM and the University of Cyprus; and in Tunisia, by INP staff Lotfi Cherif, Lotfi Aïcha Ben Abed Kahloun, Mohamed Charfa, Hamdi Dridi, Fatma Ghanem, and Martha Demas Habiba Chebil, and GCI staff and consultants Niki Savvides, Thomas Roby Elsa Bourguignon, Sibylla Tringham, and Kenza Kahrim. Conference interpreters Anne-Marie Driss, who also translated the preconference abstracts, Mohamed Ali Ben

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Remerciements

a réussite de l’organisation de la 9e Conférence de que par le personnel du GCI et les consultants Niki Savvides, l’ICCM ainsi que la publication des actes ont été réali- Elsa Bourguignon, Sibylla Tringham et Kenza Kahrim. Lsées grâce à l’engagement et aux eff orts de nombreuses Les interprètes de conférences Anne-Marie Driss, qui personnes. Au cours de la phase de planifi cation, le Comité a également traduit les résumés pré-conférence, Mohamed scientifi que du Bureau (Demetrios Michaelides, Jeanne Ali Ben Yedder et Mourad Boulares, ont facilité avec com- Marie Teutonico, Roberto Nardi, Évelyne Chantriaux et John pétence la communication entre le français et l’anglais. Elsa Stewart) ont consacré à la fois leur temps et leur compétence Bourguignon, Sibylla Tringham, Niki Savvides et Kenza à la conceptualisation des thèmes de la conférence ainsi qu’au Kahrim ont assumé le rôle de rapporteur de séance en rédi- choix des communications. geant les résumés pour inclusion dans la présentation fi nale. En Tunisie, grâce au soutien de son directeur, Kathleen Louw et Cynthia Godlewski ont assuré la Mohammed Béji Ben Mami, les cadres de l’INP, Saloua coordination des Actes pour le GCI et Tevvy Ball et Pamela Zangar, Fathi Bejaoui, Habib Ben Younes, Tahar Ghalia, Heath ont respectivement géré le projet et la coordination Mounir Fantar et Féthi Chelbi, ont participé activement à la de la production pour le service des publications du Getty. préparation de la conférence et des visites aux sites à mosaï- Gary Hespenheide a dirigé la conception du livre. Elsa ques et aux musées. L’archéologue Jean-Pierre Darmon a Bourguignon a fourni son assistance pour la mise en forme de partagé ses connaissances approfondies, acquises après de la transcription des débats. Le travail éditorial préliminaire nombreuses années d’expérience, pendant les visites sur le des communications a été fait par Anne Kurashige ; le travail terrain. Les techniciens d’entretien des mosaïques de l’INP éditorial fi nal sur l’ensemble des Actes a été assuré par Sheila TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) ont également contribué aux visites sur les sites en fournis- Berg (anglais) et Sabine de Valence (français). Les résumés et sant une démonstration des techniques et des résultats de leur textes introductifs ont été traduits de l’anglais et du français travail sur les mosaïques. par Anne-Marie Driss. Kathleen Louw (GCI), a assumé avec compétence la Au nom du GCI et de l’INP, nous tenons à exprimer nos lourde tâche de la coordination de l’organisation pratique de sincères remerciements à toutes ces personnes pour leur contri- la conférence et du tour post-conférence. Elle a été effi cace- bution à la réussite de la conférence et de cette publication. ment aidée lors de la phase préparatoire par Niki Savvides au nom de l’ICCM et l’Université de Chypre ; et en Tunisie par Aïcha Ben Abed le personnel de l’INP, Lotfi Cherif, Lotfi Kahloun, Mohamed Martha Demas Charfa, Hamdi Dridi, Fatma Ghanem et Habiba Chebil ainsi Thomas Roby

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Opening Remarks of the President of the ICCM on the Occasion of the 9th Conference

n the three years since the 8th ICCM Conference, in Mathematics, and the Institute of Cemetery and Cremation Th essaloniki, Greece (2002), more has been achieved Management! Iby the ICCM than ever before in its history. It is heart- Th e creation of the Web site was one step toward giving ening and encouraging to see how much has been accom- the ICCM a more permanent and offi cial character, which was plished, especially considering that the ICCM has little steady one of the recommendations of the Th essaloniki conference. funding and everything is done on a voluntary basis. Since Th e next step in the same direction was the offi cial registra- Th essaloniki, the proceedings of three conferences have tion of the ICCM as an organization with legal status. Th e appeared. In fact, we are now entirely up to date with our pub- committee was founded in 1977, and not having legal status lications. First, there was the long-overdue publication of the did not matter so much at the beginning, when membership 6th ICCM Conference, in Nicosia, Cyprus. Th anks to the off er was moderate and our activities limited. With improvement of assistance from Nicholas Stanley-Price, director-general of in both these directions, however, and with stricter controls ICCROM and board member of our committee, the volume on international fi nancial transactions, it became imperative appeared in 2003. Th en came the proceedings of the 7th ICCM to settle this matter. Aft er exploring several alternatives with Conference, held in Arles and Saint-Romain-en-Gal, France, board members, all of which proved legally and fi nancially in 1999. Due to the hard work of our board member Patrick problematic, I moved forward with registering the ICCM on Blanc, in collaboration with Véronique Blanc-Bijon, Évelyne the Cyprus Register of Companies. Th is now provides full Chantriaux, and Marie-Laure Courboulès, the proceedings of legal status for the ICCM as a nonprofi t organization with the that conference were also published in 2003. Finally, another ability to open an account to receive and disburse funds. of our board members, Charalambos Bakirtzis, has managed Attendance at the ICCM conferences has been building to get the proceedings of the 8th ICCM Conference published steadily over the years, and these meetings have become one in time for the Tunisia conference—a real achievement. of the most important international forums for the discus- Another milestone has been the creation of an offi cial sion of all issues related to mosaic conservation. Th e Tunisia ICCM Web site, www.iccm.pro.cy. Th anks to the assistance conference is, in fact, the largest conference ever, with 244 par- of Niki Savvides and technical support from the University of ticipants representing thirty countries. Th is is the best proof of Cyprus, this long-overdue public face of the ICCM has been the ICCM’s success. achieved. We hope this will serve as a means of outreach to the No doubt the location of the meeting in Tunisia, a coun- larger conservation community and the general public, as well try with an enviable cultural heritage, especially in ancient as an important source of information to our membership. But mosaics, has encouraged participation. For this I would like beware: memorize the address, because a search for ICCM on to thank the Institut National du Patrimoine and its director- the Internet will lead to, among other sites, the International general, Mohammed Béji Ben Mami, as well as our board Center for Cosmetic Medicine, the International Congress on member Aïcha Ben Abed, for undertaking to host this meet- Cognitive Modelling, the International Congress of Chinese ing and encouraging participation from the Maghreb and

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North Africa as a whole, a region that hitherto was poorly I would like to express my deep gratitude to the Getty represented at our conferences. Although this is the fi rst of our Foundation for giving us a generous grant, with which it has international conferences to take place in Tunisia, the involve- been possible to invite a considerable number of colleagues ment of this country with the ICCM goes back to the very from the Arab-speaking world (both North Africa and the beginnings of the organization. Tunisia has always been repre- Near East) and from Turkey. It is wonderful to have such good sented on the board, fi rst by Mongi Ennaïfer and since 1992 by representation from many countries that were either under- Aïcha Ben Abed. Th rough them and the support of the Institut represented or not represented at all at previous conferences. National du Patrimoine, Tunisia hosted the second meeting of Finally, I wish to acknowledge the contribution of the the ICCM, in 1978, and two meetings of the board, combined University of Cyprus, which provided all offi ce and equipment with Roundtables, in 2001 and 2004. I am delighted that this support for the ICCM Secretariat and, above all, agreed to long collaboration has continued with the 9th conference. manage the grant money without overhead charges. Another agent without which this meeting would not Th e theme of this year’s conference is “Lessons Learned.” have been possible is the Getty Conservation Institute, which Aft er twenty-eight years of discussions and conferences on I would like to thank in the person of its director, Timothy specifi c themes, the time was ripe for casting a look back- Whalen, and its associate director and ICCM board member, ward and refl ecting on what has been happening, both in Jeanne Marie Teutonico. Th e GCI’s role in the organization theory and in practice, during all these years in the world of of this conference has been invaluable. Th e éminence grise in mosaic conservation. We have a stimulating program in front this aff air is Martha Demas, senior project specialist at GCI, of us, with some forty-fi ve papers, twenty-fi ve posters, and who, whether from Los Angeles or China, has been involved three video presentations. But don’t worry; there is plenty with and kept a watchful eye on every step in the organization of fun, too. Th anks to our hosts, you will enjoy some superb process. Kathleen Louw, senior project coordinator, has taken receptions that, judging by my past experience, will be truly most of the brunt of the organization and logistics of this con- unforgettable. And there are also the excursions to Th uburbo ference, and I am grateful to her for doing a superb job. I also Majus, Jebel Oust, Neapolis, Carthage, and the mythical Bardo thank the GCI for supporting Niki Savvides, who assisted me Museum. during the organization of this conference. Niki has been my I wish you all a most profi table and enjoyable stay in right hand over the past few months. My infi nite thanks go to Tunisia and, above all, thank you all for coming and support- all of them for their good work. ing the work of the ICCM. As in the past, the spiritual mother of the ICCM, ICCROM, through its director-general, Nicholas Stanley- Demetrios Michaelides Price, has given its support, this time by providing the transla- President, International Committee for the tions of the abstracts into Arabic—most important for this Conservation of Mosaics meeting taking place in North Africa. November 29, 2005 TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S)

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Allocution d’ouverture du Président de l’ICCM à l’occasion de la 9e Conférence

u cours des trois années qui se sont écoulées depuis allez vous retrouver, entre autres, sur le Centre international la 8e Conférence de l’ICCM tenue à Th essalonique, pour la médecine cosmétique, le Congrès international de la AGrèce (2002), l’ICCM a accompli plus qu’il n’a jamais modélisation cognitive, le Congrès international des mathé- fait auparavant. C’est à la fois rassurant et encourageant de matiques chinoises et l’Institut pour la gestion des cimetières constater ce qui a été accompli, sachant notamment que et de la crémation ! l’ICCM ne dispose pas d’un fi nancement régulier conséquent La création du site Web marque un pas en avant dans et que tout est basé sur le volontariat. Depuis Th essalonique, nos eff orts pour doter l’ICCM d’un caractère plus permanent les actes de trois conférences ont été publiés et nous sommes et offi ciel, conformément à une des recommandations de la maintenant à jour avec nos publications. Tout d’abord a paru conférence de Th essalonique. L’étape suivante a été l’enregis- la publication tant attendue des actes de la 6e Conférence à trement de l’ICCM pour lui donner un statut juridique. Le Nicosie, Chypre. Grâce à l’off re d’aide de Nicholas Stanley- comité a été fondé en 1977, et au départ l’absence de statut juri- Price, Directeur général de l’ICCROM et membre du bureau dique importait peu car les membres n’étaient pas nombreux de notre comité, le volume est paru en 2003. Puis ce fut le et les activités étaient limitées. Cependant, ces deux aspects tour des actes de la 7e Conférence de l’ICCM tenue à Arles ont évolués avec le temps et de plus, les contrôles sont devenus et Saint-Romain-en-Gal, France, en 1999. Grâce aux eff orts beaucoup plus stricts en matière de transactions fi nancières considérables du membre de notre bureau, Patrick Blanc, internationales. Il est donc devenu urgent de trouver une solu- en collaboration avec Véronique Blanc-Bijon, Évelyne tion. Après avoir étudié, avec les membres du Bureau, les diff é- Chantriaux et Marie-Laure Courboulès, les actes de cette rentes possibilités qui posaient toutes des diffi cultés juridiques conférence ont été publiés en 2003. Finalement, un autre et fi nancières, j’ai décidé d’enregistrer l’ICCM au registre des membre de notre bureau, Charalambos Bakirtzis, a réussi à sociétés de Chypre. assurer la publication des actes de la 8e Conférence à temps L’ICCM dispose désormais d’un statut juridique en tant pour la conférence, véritable tour de force. qu’organisation à but non lucratif qui lui permet d’ouvrir un La création du site web offi ciel de l’ICCM (www.iccm. compte pour recevoir et débourser des fonds. pro.cy) a marqué une autre étape importante. Grâce à l’aide La participation aux conférences de l’ICCM augmente de Niki Savvides et au soutien technique de l’Université de régulièrement et ces réunions constituent désormais un des Chypre, cette vitrine publique de l’ICCM est enfi n devenue forums les plus importants pour discuter des problématiques réalité. Nous espérons que ce site constituera le moyen de liées à la conservation des mosaïques. Cette conférence en s’ouvrir plus largement sur la communauté de la conserva- Tunisie est en eff et la plus importante de toutes, avec 244 tion ainsi que sur le grand public, et s’avérera une source participants représentant trente pays. C’est bien la preuve du d’information importante pour nos membres. Seulement, succès de l’ICCM. veillez à bien vous souvenir de l’adresse car si vous faites une Il est certain que le fait que la réunion se tienne en Tunisie, recherche sur l’Internet pour trouver le site de l’ICCM vous pays au riche patrimoine culturel, tout particulièrement en ce

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qui concerne les mosaïques anciennes, a encouragé cette par- Price, a apporté son soutien, cette fois en fournissant la tra- ticipation. A cet égard, je tiens à remercier l’Institut National duction des résumés en arabe, essentiel pour cette réunion en du Patrimoine et son Directeur général, Mohammed Béji Ben Afrique du Nord. Mami, ainsi qu’Aïcha Ben Abed, membre de notre bureau, Je souhaiterais exprimer ma profonde reconnaissance pour avoir entrepris d’accueillir cette réunion et encouragé la à la Fondation Getty pour nous avoir octroyé une généreuse participation de l’Afrique du Nord dans son ensemble, région subvention qui nous a permis d’inviter un nombre impor- qui jusqu’ici n’était pas bien représentée à nos conférences. tant de collègues du monde arabophone (aussi bien d’Afrique Même si cette conférence est la première de nos conférences du Nord que du Proche-Orient) et de Turquie. Nous nous internationales à être organisée en Tunisie, l’implication de réjouissons de voir une représentation aussi large de plusieurs ce pays dans les travaux de l’ICCM remonte aux tous débuts pays qui auparavant étaient soit sous-représentés soit pas de l’organisation. La Tunisie a toujours été représentée au sein représentés du tout à nos conférences. de notre bureau, d’abord par Mongi Ennaïfer et depuis 1992 Finalement, je souhaiterais noter la contribution de par Aïcha Ben Abed. Grâce à eux et au soutien de l’Institut l’Université de Chypre, qui nous a fourni tout le soutien maté- National du Patrimoine, la Tunisie a accueilli la deuxième réu- riel pour le Secrétariat de l’ICCM et surtout, s’est chargée de nion de l’ICCM, en 1978, et deux réunions du bureau en même gérer la subvention sans prélever de frais. temps que des tables rondes, en 2001 et 2004. Je me réjouis que Le thème de la conférence cette année est « Leçons rete- cette longue collaboration se poursuive avec la 9e Conférence. nues ». Après vingt-huit ans de discussions et de conférences Une autre organisation sans laquelle cette réunion sur des thèmes spécifi ques, le temps est venu de regarder en n’aurait pas été possible est l’Institut Getty de Conservation, arrière et de réfl échir sur l’évolution qui a eu lieu, au cours de que je tiens à remercier à travers son directeur Timothy ces années dans le monde de la conservation des mosaïques, Whalen et son directeur associé et membre du Bureau de du point de vue de la théorie et de la pratique. Un programme l’ICCM, Jeanne Marie Teutonico. Le rôle du GCI dans l’orga- stimulant nous attend : environ quarante-cinq présentations, nisation de cette conférence a été primordial. Martha Demas, vingt-cinq posters et trois présentations vidéos. Mais ne vous spécialiste de projet en chef auprès du GCI, est l’éminence inquiétez pas, nous allons également nous distraire. Grâce grise dans cette aff aire et, que ce soit de Los Angeles ou à nos hôtes, vous allez assister à de superbes réceptions qui, de Chine, elle s’est impliquée et a surveillé chaque étape du si je me réfère à mon expérience, seront inoubliables. Nous processus d’organisation. Kathleen Louw, coordinatrice de aurons également une excursion à Th uburbo Maius, Jebel projet en chef, s’est chargée d’une grande partie de l’organisa- Oust, Neapolis, Carthage, et au mythique Musée du Bardo. tion logistique de cette conférence et je lui suis reconnaissant Je vous souhaite tous un séjour intéressant et agréable pour le travail formidable qu’elle a fait. Je souhaite également en Tunisie et surtout, vous remercie tous d’être venus soute- remercier le GCI pour le soutien apporté à Niki Savvides, qui nir le travail de l’ICCM. m’a aidé pour l’organisation de ce congrès. Niki a été mon bras droit au cours des derniers mois. Je les remercie tous Demetrios Michaelides TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) pour leur travail remarquable. Président, Comité International pour Comme par le passé, la mère spirituelle de l’ICCM, la Conservation des Mosaïques l’ICCROM, à travers son Directeur général, Nicholas Stanley- 29 novembre 2005

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Introduction

Aïcha Ben Abed, Martha Demas, and Thomas Roby

he theme of the 9th ICCM Conference in Tunisia not always achieve the hoped-for level of analysis and critical was “Lessons Learned: Refl ecting on the Th eory and evaluation. It did, however, bring to the fore the great strides TPractice of Mosaic Conservation.” It seemed appro- that have been made in the fi eld of mosaic conservation, as priate that aft er almost thirty years of ICCM conferences, well as the weaknesses that remain to be addressed. Th e key- the mosaic conservation fi eld should look back on its expe- note speech, by Gaël de Guichen and Roberto Nardi, surveyed riences and begin to draw conclusions about what has been the history and development of mosaic conservation over the accomplished and where the fi eld needs to go to improve con- past fi ft y years. In the half century since it began to emerge as servation of our ancient mosaic heritage. To this end, the orga- a distinct fi eld of endeavor, mosaic conservation has broad- nizers sought papers that would refl ect on theory and practice, ened its scope and deepened its awareness of the mosaic in its addressing how and why they have changed and what has context, the need for holistic planning, the types of training been learned over the years, or present results of an evaluation required for managing and conserving sites with mosaics, and of the many aspects of mosaic conservation: documentation, the importance of documentation and compatible treatment training, site management, maintenance, in situ conservation materials, in particular the use of lime. treatments, lift ing and re-laying, and interventions such as Th e ICCM conferences have been instrumental in eff ect- sheltering and reburial. ing the theoretical shift from conservation of mosaics by detach- Th e four days of conference papers were organized ment to conservation in situ. Th e divisions of the past between according to seven subthemes, which have been retained in this those who practiced conservation through lift ing of mosaics publication of the conference proceedings: Evaluating Mosaic and those who advocated in situ conservation have diminished, Practice, Caring for Mosaics in Museums, Documenting and as practitioners have come to accept that lift ing should happen Assessing Sites at Risk, Managing Sites with Mosaics, Sheltering much less oft en than it still does but that in certain instances Mosaics, Training of Conservation Practitioners, and Case it is the last and only option for the future conservation of a Studies, in which specifi c interventions or projects were pre- mosaic. As pointed out in the session on documenting and sented. Th e discussions following each theme, which animated assessing sites at risk, some of those circumstances—mainly the conference and provided valuable insights, have been in the form of development pressures and looting—are unfor- edited for clarity but otherwise remain unchanged.1 Sixteen tunately still prevalent and even increasing in many countries. posters presented at the conferences have also been incorpo- Nevertheless, it is a true sign of maturation that the discourse on rated in the proceedings. Th e main points that emerged in the mosaic conservation has been able to move beyond the in situ/ themed sessions were summarized in the closing session of ex situ debate to a more nuanced approach to decision making the conference and are included here as Part Eight, Summary in which an assessment of the mosaic’s signifi cance, its physical Conclusions and Recommendations. condition, and its management context are considered. Th e conference, which invited refl ection on mosaic Despite the change in attitude in relation to the system- conservation as practiced over the past several decades, did atic detachment of mosaics, participants in the session on

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caring for mosaics in museums drew attention to the problems well recognized and advocated, deciding whether a mosaic that are oft en faced by museums possessing those mosaics is lift ed or left in situ, and what type of treatment or storage that were detached long ago and frequently relaid on cement it receives, is equally infl uenced by the management context support panels or otherwise stored in poor conditions. To in which the site exists. Th e increasing attention to the role ignore this situation means to condemn thousands of mosaics of maintenance and monitoring for successful in situ conser- stockpiled both at sites and in museums. Th e session provided vation has been evident in previous ICCM conferences, but examples of comprehensive assessment of museum collections to be successful, new profi les of personnel working on sites to reverse this situation through new initiatives of conserva- (from technicians to site managers) and training opportunities tion, study, and display. are required. Several papers in the training session presented While in situ conservation is now strongly advocated recent initiatives for mosaic conservation technicians in the by the profession, the means of achieving it remain problem- Middle East and in Tunisia, refl ecting the growing recognition atic for both technical and managerial reasons. As a technical that in situ conservation requires personnel with the skills to intervention, in situ conservation requires an understanding maintain mosaics in a stable condition. Th is in turn requires of the physical condition and the causes of deterioration of a government authority willing and able to establish the req- mosaics in their original setting and the ability to mitigate uisite management organization and commit the resources the oft en complex factors at play. A review of the literature to hire and sustain a corps of conservation technicians and on deterioration and treatment presented in the fi rst session conservators. It was also noted during the training session that revealed that most published work focuses on description of there is no coordination among the initiatives, so there is little treatments carried out; there is a dearth of comprehensive and learning from the experiences of others. systematic accounts of deterioration processes leading to the Bringing these assessments of values, physical condition, development and implementation of mitigation strategies. and management context together in the decision- making Th e lack of evaluation of the eff ectiveness of previous process is the role of site management. Th e need for better site treatments or preventive measures such as sheltering and management and sustainable solutions loomed large in many reburial of mosaics is another frequently cited issue in the fi eld of the presentations at the 9th conference. A common view if we are to achieve a better understanding of what is eff ective expressed in the papers from the management session was for in situ conservation. It was in part to remedy this situation that the fi eld must address mosaic conservation as an element that the organizers selected the theme of the conference. Th e of overall site management while also taking a more long- response, however, especially with regard to evaluating treat- term approach to ensure the sustainability of conservation ment, was disappointing. One reason may be that practitioners, interventions. especially those working in private practice, rarely have the An essential aspect of a long-term and sustainable opportunity and means to critically assess prior work. approach to preserving our ancient mosaic heritage in the best Th e session devoted to shelters did include evaluation possible condition will be for national authorities to establish initiatives that are currently under way, and the case studies and policies for conservation and public awareness, taking into TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) posters dealing with reburial of mosaics attest to the strong inter- account their personnel and fi nancial resources. Th e interna- est in these methods. Both sheltering and reburial are important tional community of mosaic conservation professionals will measures for preserving mosaics in situ, but they have diff erent also need to assume a more active role in coordinating the aims and require diff erent management responses. Especially many positive experiences of mosaic conservation carried out concerning reburial, however, there are divergent opinions in diff erent regions to move the fi eld forward. We feel confi - about effi cacy and appropriateness. It is a topic that warrants dent that the publication of the papers from the ICCM confer- further in-depth discussion at future ICCM conferences in ences is one important step in that direction. order to achieve more informed opinions and consensus. Th e importance of context for understanding mosaics and the centrality of mosaics in “making a site,” especially Notes when linked with the growth in tourism to archaeological 1 Th e transcripts of the discussions from session 3, Documenting sites, was highlighted at the 6th ICCM Conference, in Nicosia. and Assessing Sites at Risk, were unfortunately not recorded due While the values that warrant in situ conservation are now to mechanical failure of the taping equipment.

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Introduction

Aïcha Ben Abed, Martha Demas et Thomas Roby

a 9e Conférence de l’ICCM organisée en Tunisie a eu sions à thème ont été résumés lors de la session de clôture de pour thème « Leçons retenues : Les enseignements tirés la conférence et sont présentés ici dans la Partie VIII, Résumé Ldes expériences passées dans le domaine de la conserva- des Conclusions et Recommandations. tion des mosaïques ». Après près de trente ans de conférences La conférence, qui invitait à une réfl exion sur la conser- de l’ICCM, il semblait utile de permettre au domaine de la vation des mosaïques telle que pratiquée au cours des derniè- conservation des mosaïques de faire le point sur son expéri- res décennies, n’a pas toujours atteint le niveau d’analyse et ence passée et de commencer à tirer des conclusions par rap- d’évaluation critique souhaité. Toutefois, elle a mis en évi- port à ce qui a été réalisé tout en envisageant les orientations dence les progrés accomplis dans le domaine de la conser- qui permettraient d’améliorer la conservation de notre patri- vation des mosaïques, ainsi que les faiblesses auxquelles il moine de mosaïques anciennes. A cette fi n, les organisateurs conviendrait de remédier. Dans leur discours-programme ont sollicité des communications qui soit proposeraient une Gaël de Guichen et Roberto Nardi ont passé en revue cin- réfl exion sur la théorie et la pratique, sur la manière et les quante ans d’histoire et d’évolution de la conservation des raisons de leur évolution et sur les leçons retenues au fi l des mosaïques. Pendant ce demi-siècle, depuis que le domaine a années, soit qui présenteraient les résultats d’une évaluation commencé à affi rmer sa spécifi cité, la conservation des mosaï- d’un des nombreux aspects de la conservation des mosaïques : ques a élargi son champ d’application et approfondi sa prise documentation, formation, gestion des sites, entretien, traite- de conscience de la mosaïque dans son contexte, du besoin ments de conservation in situ, dépose et repose et interven- d’adopter une planifi cation globale, des types de formation tions tels que les abris et le réenfouissement. nécessaires pour gérer et conserver les sites à mosaïques, et de Les quatre jours consacrés à la présentation des com- l’importance de la documentation et des matériaux de traite- munications ont été organisés selon sept sous-thèmes qui ment compatibles, en particulier l’utilisation de la chaux. ont été retenus également dans cette publication des Actes Les conférences de l’ICCM ont joué un rôle décisif de la conférence : Évaluation de la pratique des mosaïques, pour opérer un changement de cap théorique et passer de Entretien des mosaïques dans les musées, Documentation et la conservation des mosaïques par dépose vers la conserva- évaluation des sites à risque, Gestion des sites à mosaïques, tion in situ. Les divisions qui existaient entre ceux qui pra- Mise sous abri des mosaïques, Formation des praticiens, et tiquaient la conservation en déposant les mosaïques et ceux Études de cas, réunissant les interventions spécifi ques ou les qui prônaient la conservation in situ ont diminué. Les prati- projets. Les débats faisant suite à chaque thème, animant la ciens ont commencé à accepter que le recours à la dépose ait conférence en y apportant une réfl exion précieuse, ont fait lieu beaucoup moins souvent mais que dans certains cas cela l’objet d’un travail de mise en forme1 pour assurer davantage puisse constituer la dernière et unique option pour la conser- de clarté, sans pour autant subir de modifi cation. Les seize vation d’une mosaïque. Comme il a été dit lors de la session posters présentés à la conférence ont également été inclus sur la documentation et l’évaluation des sites à risques, cer- dans les actes. Les points principaux qui ont émergé des ses- taines circonstances – principalement des pressions dues au

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développement ou au pillage – subsistent malheureusement La session consacrée aux abris a fait état de quelques toujours et gagnent même de l’ampleur dans de nombreux initiatives en cours en matière d’évaluation et les études de pays. Cependant, c’est un véritable signe de maturation que le cas et posters se rapportant aux réenfouissements des mosaï- discours sur la conservation des mosaïques ait pu dépasser le ques témoignent du grand intérêt porté à ces méthodes. La simple débat pour préparer une prise de décisions beaucoup mise sous abris ainsi que le réenfouissement sont des mesures plus nuancée tenant compte de l’évaluation de l’importance intéressantes pour préserver les mosaïques in situ, mais ils de la mosaïque, de son état matériel et du contexte de sa répondent à des objectifs diff érents et requièrent des mesures gestion. de gestion diff érentes. Notamment en ce qui concerne le réen- Malgré l’évolution des attitudes par rapport à la dépose fouissement, les avis sont partagés sur son effi cacité et sa per- systématique des mosaïques, les participants à la session sur tinence. C’est un sujet qui mérite d’être davantage approfondi l’entretien des mosaïques dans les musées ont attiré l’atten- lors des prochaines conférences de l’ICCM afi n de permettre tion sur les problèmes auxquels font souvent face les musées des opinions mieux informées et susciter un consensus. qui abritent des mosaïques déposées depuis longtemps et L’importance du contexte pour comprendre les mosaï- souvent reposées sur des supports en ciment ou alors stoc- ques et le rôle central des mosaïques qui « font un site », par- kés dans de mauvaises conditions. Ne pas reconnaître cette ticulièrement en conjonction avec la croissance du tourisme situation signifi e la condamnation de milliers de mosaïques sur les sites archéologiques, sont des aspects évoqués lors de stockées à la fois sur les sites et dans les musées. Les sessions la 6e Conférence à Nicosie. Alors que les valeurs justifi ant la ont proposé des exemples d’évaluations complètes de collec- conservation in situ sont désormais reconnues et prônées, la tions de musées pour remédier à cette situation à travers des décision de savoir si une mosaïque doit être déposée ou laissée nouvelles initiatives de conservation, étude et exposition. in situ, et quel type de traitement ou de stockage lui appli- Si la conservation in situ est à présent fortement préco- quer sont des questions qui sont également infl uencées par le nisée par la profession, les moyens d’y parvenir demeurent contexte de gestion du site. L’attention de plus en plus grande problématiques pour des raisons à la fois techniques et de accordé à l’entretien et au suivi pour assurer une conservation gestion. En tant qu’intervention technique, la conservation in in situ réussie a été évoquée lors des conférences précédentes situ nécessite une connaissance de l’état matériel et des causes de l’ICCM mais pour assurer la réussite il est nécessaire de de détérioration des mosaïques dans leur cadre d’origine et la disposer de nouveaux profi ls de personnel travaillant sur les capacité d’atténuer les facteurs souvent compliqués qui entrent sites (des techniciens jusqu’aux gestionnaires de site) ainsi que en jeu. Une étude de la documentation sur la détérioration et d’opportunités de formation. Lors de la session consacrée à la les traitements présentée au cours de la première session a formation, plusieurs communications ont fait état d’initiatives montré que la majorité des travaux publiés sont consacrés à la récentes concernant les techniciens pour la conservation des description des traitements eff ectués ; il existe peu de comptes mosaïques au Moyen-Orient et en Tunisie, refl étant ainsi le rendus complets et systématiques des processus de détériora- constat de plus en plus partagé que la conservation in situ tion qui conduisent au développement et à la mise en œuvre de requiert un personnel capable de maintenir les mosaïques TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) stratégies d’atténuation. dans un état stable. Cela exige aussi une autorité de tutelle Le manque d’évaluation de l’effi cacité des traitements avec la volonté et la capacité de mettre en place une organi- précédents, ou des mesures préventives telles que la mise sation de gestion adéquate et d’engager les ressources néces- sous abri ou le réenfouissement des mosaïques est souvent saires pour embaucher et maintenir un corps de techni- évoqué. Cela permettrait une meilleure compréhension des ciens de la conservation et de conservateurs-restaurateurs. approches les plus effi caces pour la conservation in situ. C’est Il a également été constaté lors de la session sur la formation en partie pour remédier à cette situation que les organi- qu’aucune coordination existe entre les initiatives, empêchant sateurs ont choisi le thème de la conférence. Toutefois, la ainsi la transmission de l’expérience. réponse, particulièrement en ce qui concerne l’évaluation Le rôle du gestionnaire de site est de rassembler ces éva- des traitements, a été décevante. Cela pourrait s’expliquer, luations des valeurs, de l’état physique et du contexte de ges- entre autres, par le fait que les professionels, notamment tion pour les intégrer dans le processus décisionnel. Plusieurs privés, ont rarement l’occasion ou les moyens d’entreprendre communications présentées à la 9e Conférence ont insisté sur une évaluation critique des travaux précédents. la nécessité de mettre en place une meilleure gestion des sites

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et de trouver des solutions durables. Lors de la session sur la assumer un rôle dans la coordination des nombreuses expé- gestion, il y a eu un accord général pour dire que la conser- riences positives en ce domaine dans diff érentes régions pour vation des mosaïques doit être considérée comme un élément le faire avancer. Nous sommes confi ants que la publication de la gestion d’un site dans son ensemble tout en adoptant des communications des conférences de l’ICCM constitue un une approche à plus long terme afi n d’assurer la durabilité des pas important dans cette direction. interventions de conservation. Un aspect essentiel d’une approche à long terme et durable à la préservation du patrimoine de mosaïques anciennes Notes dans le meilleur état possible serait que les autorités natio- 1 La transcription des débats de la session 3, Documentation nales mettent en place des politiques de conservation et sen- et évaluation des sites à risque, n’a malheureusement pas sibilisation du public, en tenant compte de leurs ressources pu aboutir à cause d’un problème technique du matériel fi nancières et humaines. La communauté internationale des d’enregistrement. professionnels de la conservation des mosaïques devra aussi TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 5 TJ14-3 P i-006 200L CTP.indd 5 3/3/08 10:47:32 AM i Cyan Magenta Yellow Black

PART ONE

Evaluating Mosaic Practice TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 7 TJ14-3 P007-066 200L CTP.indd 7 3/3/08 1:47:09 PPMM Cyan Magenta Yellow Black TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S)

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Mosaic Conservation: Fifty Years of Modern Practice

Gaël de Guichen and Roberto Nardi

Abstract: Th e practice of mosaic conservation has evolved sig- known sites. During the postwar period in Europe massive nifi cantly over the past several decades. Fift y years ago mosaics construction and reconstruction was undertaken, and dis- were approached as isolated objects, without context, and inter- coveries of mosaics occurred more frequently throughout the ventions were undertaken without adequate planning. Th ere continent. Th is does not mean, however, that these artifacts were limited options for conservation strategies (detachment were ultimately preserved. According to a 1971 study by the was the main option available); the workforce consisted mainly French engineer Claude Bassier, of 660 pavements found in of artisans, craft spersons, or carpenters; and materials were France since 1870 and published by archaeologists, at least 83 limited to cement, gypsum, or adhesives. Th is paper reviews the percent were abandoned, destroyed, or lost (Bassier 1975). Th e changing philosophy and practice of mosaic conservation, lead- remaining pavements—those whose subjects were fi gurative ing to the current state of the art. and considered valuable—were, according to the traditional techniques of the time, systematically removed from archaeo- Résumé : La pratique de la conservation des mosaïques a consi- logical sites. Some were relaid on concrete slabs; others were dérablement évolué au cours des dernières décennies. Il y a cin- abandoned in storage, where many remain today (fi g. 1). quante ans, la mosaïque était abordée comme un objet isolé et sans contexte et les interventions étaient eff ectuées sans planifi - cation adéquate. En décidant d’une stratégie de conservation les options étaient très limitées (la dépose constituait l’option prin- cipale), les intervenants étaient principalement des artisans tels que les menuisiers et les matériaux se limitaient au ciment ou au plâtre. A partir de ces débuts, la présentation retrace l’évolution de la philosophie et de la pratique de la conservation des mosaï- ques, pour arriver aux « méthodes de pointe » actuelles.

In a sense the conservation of mosaics is a practice as old as the making of mosaics themselves. Today one can fi nd ancient mosaics with patches made as part of maintenance when the fl oors were still in use. In more recent centuries restoration was widely practiced on objects of antiquity, including mosaics. And from the fi rst decades of the twentieth century we have fi ne examples of restorations.

Before the mid-twentieth century, discoveries of mosa- FIGURE 1 Mosaics lift ed from their original sites and placed in ics occurred primarily during archaeological excavation of storage. Photo by Roberto Nardi.

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10 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

In the early postwar period strategies for mosaic conser- In the 1960s a dramatic evolution in mosaic conserva- vation were very limited; detachment was the primary option tion began. Two important professional fi gures came to prom- available. Interventions were typically undertaken with- inence in this decade: Rolf Wihr in Cologne, Germany, and out adequate planning and with a workforce that consisted Claude Bassier in Périgueux, France. Wihr was a conservator- mainly of artisans, craft spersons, or carpenters. Conservation restorer, working at the Rheinisches Landesmuseum in Trier. practice was based solely on empirical knowledge, and the Bassier, in private practice, was called in on rescue excava- materials used by practitioners were limited to cement, gyp- tions when mosaics were discovered. He was able to arrive sum, and adhesives. In addition, documentation was lack- within two days, with trucks, a crate, and a tent with heating ing. Practitioners worked in isolation, without the benefi t of systems, ready to work, even in winter. Both Wihr and Bassier professional associations. An exception in the late 1950s to the introduced new approaches, which included systematic doc- typical treatment of excavated mosaics was the completion umentation, new supports (honeycomb aluminum instead of the excavation of the Villa del Casale in Piazza Armerina, of concrete), and new adhesives (resins instead of glues and Sicily (fi g. 2); there Cesare Brandi introduced the solution of cement) (Bassier 1978). But they also continued the estab- conserving the villa’s remarkable mosaics in situ and protect- lished practice of polishing the mosaic surfaces. ing the entire site (Brandi 1956; Stanley-Price 1997). A third signifi cant fi gure who advanced the fi eld tech- nologically at an early date was Antonio Cassio of the Istituto Centrale per il Restauro in Rome. Cassio, a mosaicist from a family of mosaicists, preferred a more sensitive and controlled method for detaching mosaics. He used a system typical of mosaic making itself, which permitted the detachment of mosaics in pieces averaging 25 square centimeters (Cassio 1982). Th is method substantially reduced cutting stresses—and therefore reduced damage to mosaics being lift ed. In the late 1960s, again in Italy, a diff erent fi eld—mural painting—was undergoing a theoretical and practical reevalu- ation, which would have a direct and important impact on mosaic conservation. In 1968 the International Center for the Study of the Preservation and Restoration of Cultural Property (ICCROM) joined with the Istituto Centrale per il Restauro to initiate an annual four-month course on the conservation of wall paintings. At fi rst the highlight of the course was the detachment of a wall painting, but very quickly in situ consolidation was embraced as a more appropriate method, as wall TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) paintings came to be considered an integral part of the buildings in which they occurred. Th is evolution in wall paintings conservation led to the publication in 1977 of the fundamental book for the profession, Conservation of Wall Paintings (Mora, Mora, and Philippot 1977).

Establishing the International Committee for the Conservation of Mosaics All this was in the air in 1977 when the fi rst meeting on mosaic conservation—with forty-fi ve participants—was organized FIGURE 2 Th e mosaics of the Villa Romana del Casale in Piazza Armerina, Sicily, were conserved in situ and sheltered in in Rome. At the end of this conference ten of the partici- the late 1950s. Photo by Guillermo Aldana 1993. © J. Paul Getty pants decided to establish the International Committee for the Trust. Conservation of Mosaics (ICCM) and to act as its fi rst board.

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Mosaic Conservation: Fifty Years of Modern Practice 11

Th e publication of the proceedings of the meeting, addressed the oldest construction materials known—lime-based mor- to archaeologists, conservator-restorers, technicians, adminis- tar (Ferragni et al. 1984). However, even within the ICCM, trators, and the public, was titled Mosaics, No. 1: Deterioration almost ten years of heated debate took place before lime-based and Conservation (Selvig 1978). Another important result of mortars were generally accepted and before cement applied the meeting was the recommendation to launch a course on in direct contact with mosaics was replaced. Th e use of lime- mosaic conservation. based mortars has allowed the development of in situ consoli- Th e 1977 meeting in Rome was the starting point dation and furthered the practice of maintenance in situ when for a series of regular conferences. Th e following year, the possible. (Unfortunately, despite the abundant evidence of Institut National du Patrimoine in Tunisia hosted the sec- destruction caused by cement in conservation interventions, ond conference and went on to host subsequent meetings this material is still used on mosaics—and worse, its use is still of the ICCM board. Th e latest conference, the ninth, took taught as a technique in some countries.) place in Hammamet, Tunisia, in 2005. Following each of these Another important advance that can be credited to meetings, the proceedings were published. In addition to the discussion and refl ection at several ICCM conferences was proceedings, twelve newsletters have been published. Th ese the acceptance by conservation practitioners of a planned materials represent for the profession a basic source of infor- approach to safeguarding mosaic fl oors. In 1996 a question- mation that did not exist fi ft y years ago. driven fl owchart was developed to help practitioners deter- Th e evolution in the thinking of the ICCM—and, indi- mine which of several options would be most appropriate to a rectly, the trend in its professional principles—is refl ected in particular context and set of problems (fi g. 3). Th e questions the themes of each of its conferences: related to risk, visitation, signifi cance, available resources, and archaeological investigation, and they led to consider- Rome, Italy, 1977: Deterioration and Conservation ation of a range of options, including backfi lling, lift ing and Tunis and Carthage, Tunisia, 1978: Safeguard transferring to a museum, lift ing and re-laying in situ, and Aquileia, Italy, 1983: Conservation in Situ consolidation in situ. Soria, Spain, 1986: Conservation in Situ Th e standard practice of leaving a mosaic on-site with- Palencia, Spain, 1989: Conservation in Situ out protection—or of lift ing the pavement and abandoning Faro-Conimbriga, Portugal, 1992: Conservation, it in storage—was clearly the result of a lack of planning, as Protection, Presentation well as demonstrative of the attitude of some archaeologists, Nicosia, Cyprus, 1996: Mosaics Make a Site: Th e insensitive to conservation, who felt that their work ended Conservation in Situ of Mosaics on Archaeological Sites the day they published their fi ndings. A systematic analysis of Saint-Romain-en-Gal and Arles, France, 1999: Mosaics: practical conditions can help to determine diff erent and more Conserve to Display? appropriate approaches for dealing with an excavated mosaic. Th essaloniki, Greece, 2002: Wall and Floor Mosaics: With any of these options, serious planning before implemen- Conservation, Maintenance, and Presentation tation is required. Hammamet, Tunisia, 2005: Lessons Learned: Refl ecting Th e four ICCM conferences following those dedicated on the Th eory and Practice of Mosaic Conservation to in situ conservation referenced in their titles the issues of public presentation of mosaics. As early as 1978 it was suggested It is evident that by 1983 the ICCM was pointing out the impor- in Mosaics, No. 1, that the public be involved “so that specialists tance of in situ conservation and encouraging its use whenever responsible for conservation receive support from both groups possible. In this way, it mirrored an evolution that had already and individuals. It is the public, aft er all, that benefi ts and is occurred among wall paintings specialists. served by the world-wide conservation movement” (Selvig 1978: Another principle that ICCM has come to strongly sup- foreword). Th is approach established in the mosaic conserva- port is the rejection of the use of cement in the conservation tion fi eld recognition that an objective of the conservation pro- and restoration of mosaics. It had been clear for some time fession is to present and to interpret for the public the cultural that the use of cement in the conservation of ancient monu- properties that we are engaged in conserving (fi g. 4). ments brought the risk of an increase in damage. In response, To infl uence the actual practice of mosaic conservation, the Italian conservation scientist Giorgio Torraca launched these new ideas and approaches required adequate training research in 1980 to replace cement with, paradoxically, one of at all levels. Yet the development of training did not happen TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 11 TJ14-3 P007-066 200L CTP.indd 11 3/3/08 11:21:44 AM Cyan Magenta Yellow Black

12 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

FIGURE 3 Question-driven fl owchart developed in 1996 to guide decision A. Document 6 Questions Inform the public making. for No Retrieve the 2. Is the tesserae 5 Solutions mosaic a Excavate major work? Yes B. Plan Yes Document Lift 1. Will the Mount in museum Excavate site or the Yes context be 4. Is there inevitably a risk that destroyed? No the mosaic will be sto- No C. Plan Document Yes len or van- Re-cover dalized? Maintain 3. Will the site be open No to the public? No 5. Have D. Plan/document you the Lift human and Replace in situ ﬁnancial Protect - Maintain 6. Is it Yes means to Inform the public Yes necessary show and to excavate protect under the the site? mosaic? No E. Plan/document Conserve/ restore Protect in situ Inform the public Maintain

quickly. Twelve years passed aft er the 1977 recommendation for training before the fi rst course for decision makers was initiated. Th e one-month course—organized by ICCROM in 1989 in Rome—was attended primarily by archaeologists (Melucco Vaccaro, de Guichen, and Nardi 1994). Today some of the participants of that early course are members of the ICCM board. Since that time several courses at various levels have been—and continue to be—organized. While this activity is TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) generally welcome, certain doubts exist regarding their effi cacy. Some of the sessions are considered too short—a few weeks at most—or it is felt that the trainers lack the necessary teaching ability. In some instances the production of new mosaics is taught simultaneously with conservation techniques—a ques-

FIGURE 4 Visitors watching conservation activities at the site of tionable pairing. Zippori, Israel. Photo by Roberto Nardi. An example of training appropriately adapted to the challenge faced is the technician training program launched by the GCI and Tunisia’s Institut National du Patrimoine in 1998 (fig. 5). This long-term involvement in training technicians in the care and maintenance of in situ archaeological mosaics is attempting to enhance the ability of cultural authorities in Tunisia to preserve the country’s wealth of mosaic heritage.

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Mosaic Conservation: Fifty Years of Modern Practice 13

FIGURE 5 Technicians-in-training stabilizing a mosaic pavement at the site of Th uburbo Majus, Tunisia. Photo by Kristin Kelly 2003. © J. Paul Getty Trust.

Maturing of the Profession At the same time it is evident that there are issues that have not been resolved, and a great deal of work remains to For the mosaic conservation fi eld, the past fi ft y years constitute be done. Th ere is an urgent need to properly conserve and a period of great change and maturation. Th e establishment store hundreds, if not thousands, of mosaics previously relaid and development of the ICCM has advanced the work begun on reinforced concrete or abandoned in storage. Reburial of by the Association Internationale pour l’Étude de la Mosaïque mosaics is an important tool for preserving mosaics, but it Antique (AIEMA) and later developed by the Association for requires clear protocols and a technical and fi nancial assess- the Study and Preservation of Roman Mosaics (ASPROM) in ment. Further research on the protection of mosaics from Great Britain and the Associazione Italiana per lo Studio e la biological growth would contribute to resolving a widespread Conservazione del Mosaico (AISCOM) in Italy. problem confronting the preservation and presentation of Unlike three decades ago, the scope of mosaic conserva- mosaics. Studies of the cost of maintenance of mosaics in situ tion is no longer restricted to a few square meters of tesserae are needed to help promote this approach. Assessments of recently excavated or on exhibit in a museum. It has expanded training needs for archaeologists, conservator-restorers, and to include entire mosaic complexes or sites where thousands technicians are essential to ensuring long-term protection of of square meters of mosaics are in danger. And the conservator mosaics. And fi nally, the publication of a major book on the has been joined by other professionals in the fi eld of conser- conservation and restoration of mosaics is long overdue. vation in addressing the problems of mosaic conservation. Th ese are only some of the challenges faced by the profes- Among them are conservation scientists who share an inter- sionals charged with responsibility for conserving and exhibit- est in fi nding solutions to mosaic conservation globally—and ing mosaics. Th ere is still a long way to go. Nevertheless, it is not simply through the lens of a microscope. Th at 250 col- not unrealistic to look to the future with optimism. With the leagues from thirty countries—and with many diff erent back- help of the ICCM, the great vitality demonstrated by the pro- grounds—attended the 9th ICCM Conference indicates that fession has resulted in standards of mosaic conservation prac- common problems exist and that the interest in solving them tice today that appeared almost unreachable thirty years ago. collectively is very high. Much has been accomplished, and those accomplishments form an essential foundation for the work that lies ahead. TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 13 TJ14-3 P007-066 200L CTP.indd 13 3/3/08 11:21:45 AAMM Black

14 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

Melucco Vaccaro, A., G. de Guichen, and R. Nardi. 1994. References Conservation of archaeological mosaics: Th e state of the problem Bassier, C. 1975. Conservation de pavements de mosaïque antique in the light of a recent international course. In Mosaicos, no. 5: en France. In Colloque international pour l’étude de la mosaïque Conservación in situ: Palencia, 1990: IV Conferencia general del antique: La mosaïque gréco-romaine II [Actes du IIe Colloque Comité internacional de mosaicos, ed. ICCM and ICCROM, international pour l’étude de la mosaïque antique, Vienne, 30 août– 333–40. Palencia: Excma. Diputación Provincial, Departamento 4 septembre 1971, ed. H. Stern and M. Leglay, 155–72. Paris: Édition de Cultura. A. & J. Picard et Centre National de la Recherche Scientifi que. Mora, P., L. Mora, and P. Philippot. 1977. Conservation of Wall . 1978. Some problems in the conservation of mosaics. In Paintings. London: Butterworth. Mosaics, No. 1: Deterioration and Conservation, Rome, November Selvig, F., ed. 1978. Mosaics, No. 1: Deterioration and Conservation, 1977: Proceedings of the First International Symposium on the Rome, November 1977: Proceedings of the First International Conservation of Mosaics, ed. F. Selvig, 67–80. Rome: ICCROM. Symposium on the Conservation of Mosaics. Rome: International Brandi, C. 1956. Archeologia siciliana. Bollettino dell’Istituto centrale Centre for the Study of the Preservation and Restoration of del restauro, nos. 27–28: 93–100. Cultural Property.

Cassio, A. 1982. Détachement des mosaïques—Methode du puzzle. Stanley-Price, N. 1997. Th e Roman villa at Piazza Armerina, Sicily. In Th e International Committee for Mosaics Conservation Newsletter, Conservation of Archaeological Sites in the Mediterranean Region: An no. 5: 24–27. International Conference Organized by the Getty Conservation Institute and the J. Paul Getty Museum, 6–12 May 1995, ed. M. de la Torre, Ferragni, D., M. Forti, J. Malliet, J. M. Teutonico, and G. Torraca. 1984. 65–87. Los Angeles: Getty Conservation Institute. Injection grouting of mural paintings and mosaics. In Adhésifs et consolidants: 10e Congrès international adhésifs et consolidants (Adhesives and Consolidants, Paris Congress, 2–8 September 1984, Preprints), ed. N. S. Brommelle, E. M. Pye, P. Smith, and G. Th omson, 110–16. London: International Institute of Conservation. TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S)

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Learning from Past Interventions: Evaluation of the Project to Conserve the Orpheus Mosaic at Paphos, Cyprus

Martha Demas, Thomas Roby, Neville Agnew, Giorgio Capriotti, Niki Savvides, and Demetrios Michaelides

Abstract: In 1988–89 a project to lift and re-lay the Orpheus (Aerolam® panels)—had been employed in the detachment of mosaic at Paphos, Cyprus, was undertaken by the Getty mosaics, but on a smaller scale and mainly for preservation in Conservation Institute and the Department of Antiquities, a museum context.1 Th e relaid mosaic was further protected Cyprus. Th e project was evaluated in 2004 to determine whether with what was intended to be a temporary shelter, pending it had met its intended goals and contributed to the fi eld of construction of permanent shelters by the Department of mosaic conservation. Th is paper presents the methodology for Antiquities over all the mosaics at the Paphos site. evaluation of the project as a whole, poses the main issues and Th e project to lift and re-lay the mosaic was a joint questions raised during the in situ assessment, and provides an undertaking by the Getty Conservation Institute (GCI) and overview of results and the three main lessons learned, which the Department of Antiquities, Cyprus, and constitutes one relate to the importance of values in decision making, the critical of the GCI’s earliest fi eld projects. As part of a larger initia- role of documentation, and the need for eff ective management tive of the GCI to assess some of its previous projects, it was for sustainability. decided in 2003 to evaluate the Orpheus project. Th e purpose of evaluation is to determine whether the project has met its Résumé : En 1988–89 la dépose et la repose de la mosaïque intended goals and contributed to the advancement of the d’Orphée à Paphos, Chypre, a été eff ectuée par l’Institut Getty theory and practice of conservation (and if not, why not?). de Conservation et le Département des Antiquités de Chypre. Evaluation may be thought of as an interface between the past En 2004, ce projet a fait l’objet d’une évaluation pour détermi- and the future, since it involves a systematic investigation of a ner dans quelle mesure il avait atteint ses objectifs et contribué past activity in order to inform and improve future activities. au domaine de la conservation des mosaïques. Cette communi- Th e goal, then, is to learn lessons, both the lessons of success cation présente la méthodologie d’évaluation, évoque les pro- and those of failure. blématiques survenues lors de l’évaluation in situ et résume les Th is paper presents the basic methodology developed résultats ainsi que les trois principaux enseignements, à savoir for evaluation of the project as a whole, poses the main issues l’importance des valeurs dans la prise de décisions, le rôle and questions raised during the in situ assessment, and pro- essentiel de la documentation et la nécessité d’une gestion effi - vides an overview of the results obtained and the three main cace pour assurer la durabilité. lessons learned from the assessment.

In 1988–89 an exceptional fi gural mosaic of Orpheus and the Th e Project to Lift and Re-lay the Beasts, dated to the late second/early third century c.e., was Orpheus Mosaic lift ed and relaid in situ on a new support in Paphos, Cyprus. Th e technique and materials used—rolling of the mosaic and Th e Orpheus mosaic (4.25 by 5.10 m) was excavated in 1984 re-laying on a lightweight honeycomb aluminum support by one of the authors under the auspices of the Department

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16 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

of Antiquities, Cyprus.2 It suff ered from root intrusion that adhesive and fi berglass sheets constituted the core of the proj- resulted in a few large lacunae and dislocation and loss of tes- ect. Other aspects included analysis of tesserae and mortars serae along the top part of the mosaic, destruction of its edges and a yearlong environmental monitoring of the site. Lift ing from ancient robbing of the walls of the room, subsidence and re-laying took place over two years, 1988–89, but since caused by the presence of earlier structures below the mosaic, the details of the technique are not the subject of this evalua- which became more pronounced as the subsoil dried out fol- tion, we will compress the complexity and technicalities of the lowing excavation, and lack of cohesion of the mortar of the undertaking into a very brief review of the steps involved: bedding layer (fi g. 1) (Michaelides 1991). For these reasons, particularly lack of cohesion and sub- • documentation and preparation (facing and consoli- sidence of the bedding layers, and in line with common practice dation) of the mosaic; of the Cypriot Department of Antiquities, the Orpheus mosaic • detachment of the tessellatum from the bedding was to be conserved through lift ing and re-laying. Th e tech- layers and rolling it on a wooden cylinder as it was nique of rolling the tessellatum on a large wooden cylinder (or detached; drum) was selected because the mosaic was largely intact, with- • cleaning of mortar from the back of the tessellatum out structural cracking, was accessible to large machinery, and, while on the cylinder (and again aft er it was laid face- most important, could be lift ed as a single intact, pictorial com- down) (fi g. 2); position. Th e project began in 1988, under the general direction • transport of the rolled mosaic by bulldozer to its tem- of Paolo Mora, as consultant to the GCI, and entailed three porary storage, where it was unrolled facedown; main components: lift ing and re-laying of the mosaic, train- • application of new mortar to the back of the tessella- ing of conservators in the technique, and temporary sheltering tum, followed by epoxy adhesive and fi berglass sheets; of the mosaic (see Stanley-Price 1991 for details of the project • construction of the new support, consisting of an implementation, participants, and costs). Aerolam® panel (with aluminum honeycomb core), Lift ing of the mosaic using the rolling technique and re- adhered to the prepared mosaic with epoxy; laying it on an isolating support of Aerolam® panels with epoxy • preparation of the original site with a concrete slab;

FIGURE 1 Orpheus mosaic (fore- ground) prior to being lift ed in 1988, with the Amazon and Heracles mosaic (background) already partially lift ed and relaid. Photo by Guillermo Aldana 1998. © J. Paul Getty Trust. TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S)

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The Project to Conserve the Orpheus Mosaic at Paphos 17

• reinstallation of the mosaic with panel in its original Figure 3 shows the mosaic on its Aerolam® panel aft er it location using a crane to lift it in place; and, fi nally, was relaid in its original position. • removal of the facing and fi lling of lacunae with Th e project was designed with a didactic component. mortar. It would provide conservators with hands-on experience in the rolling technique, which was infrequently used at the time but was believed to have potential for greater use as a method for lift ing and re-laying figural mosaics to avoid the potentially destructive aspects of cutting a mosaic in sections. Nine conservators from the Mediterranean region took part in the project. During Phase 1, training was divided between formal classroom lectures on other aspects of and approaches to mosaic conservation and on-site work on the Orpheus and other mosaics at Paphos. Phase 2 training was exclusively hands-on work, aimed at implementation of the project. Th e construction of a shelter to protect the Orpheus mosaic was a later addition to the original project objectives (fig. 4). It arose out of a GCI initiative to develop a lightweight, modular, and temporary shelter for protection of archaeological sites. Th e so-called hexashelter began as an experimental design by Neville Agnew that was field-tested and evaluated in 1988 at Fort Selden, New Mexico (Agnew and Coff man

FIGURE 2 Mortar being removed from the back of the Orpheus 1991; Agnew et al. 1996). In 1989 it was decided to apply the mosaic while it is rolled on the drum. Photo by Paolo Pastorello prototype to protect the Orpheus mosaic temporarily (no 1998. © J. Paul Getty Trust. more than five years) pending permanent sheltering and site

FIGURE 3 Orpheus mosaic on the Aerolam® panel relaid in its original position but before fi nal cleaning, fi lling of lacunae, and rebuilding of the surrounding walls of the room. Photo by Guillermo Aldana 1989. © J. Paul Getty Trust. TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 17 TJ14-3 P007-066 200L CTP.indd 17 3/3/08 11:21:52 AM Cyan Magenta Yellow Black

18 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

(a)

FIGURE 4A, B Th e “hexashelter,” a modular system designed as temporary protection for the Orpheus mosaic, as seen from the exterior (a) and interior (b). Photos by Martha Demas 1992. © J. Paul Getty Trust. TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S)

(b)

development for Paphos, which was at that time under discus- evaluation of previous projects was raised as an important sion as part of a World Bank loan.3 need in the field. Because the Orpheus project was the second Th e Orpheus Mosaic Project was completed in 1989 fi eld project of the GCI (founded in 1985) and the GCI was and published soon aft er (Stanley-Price 1991). Th e decision to again involved with mosaics, it was decided that an evaluation evaluate the project was prompted in part by an experts’ meet- of the Orpheus project would serve both institutional needs ing on mosaic conservation held in Cyprus in 2002, at which and those of the fi eld of mosaic conservation.

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The Project to Conserve the Orpheus Mosaic at Paphos 19

Methodology for Evaluation terms, but there were several assumptions and entrenched practices that were implicit in determining the goals of the Th e methodology used for evaluation of the project consists project. Th ese were as follows: of two parts. Th e fi rst is simply collection of background information and documentation, and needs no elaboration or • Th e artistic value of a mosaic is paramount or at least explanation, except to note that gathering such information takes precedence over historic and scientifi c values. can be time-consuming and frustrating if the documentation • Mosaics cannot be left in situ without risking their has not been archived in an orderly and accessible manner. destruction (hence the common practice of lift ing Th e second part, the analytic component, is the cru- and re-laying). cial one. Cultural heritage conservation has not developed • Lift ing of mosaics in sections, though standard models for project evaluation, but nature conservation off ers operating procedure at the time, could not be accom- plenty, as do the educational and corporate worlds. Th e mod- plished because the Orpheus mosaic—a single picto- els from nature conservation were generally more compatible rial composition—could not be easily subdivided with the aims and ways of working in cultural heritage con- into smaller panels to enable lift ing. Further, were it servation, and we thus adapted the methodology of the World to be lift ed in that manner, the result would be sub- Conservation Union,4 formerly the International Union for stantial loss of tesserae and diffi culties in aesthetic Conservation of Nature and Natural Resources. reintegration. Th e methodology is based on what are defi ned as “key • Archaeological excavation below the mosaic, to questions of evaluation.” Th ese are broad and generic, but they investigate earlier use of the site, was highly desirable bring to the fore the most salient aspects of project evalua- (from the archaeologist’s perspective) and was com- tion: relevance, eff ectiveness, impact, and sustainability. In our mon practice at the time. evaluation the key questions were answered by considering the following: In light of these assumptions and ways of operating, the situation needing improvement might be formulated in • the history of the project and all supporting retrospect as a method to lift and re-lay the mosaic in a man- documentation; ner that would cause least damage, ensure aesthetic integrity, • a new condition survey of the Orpheus mosaic and and allow excavation below it. Given that limited situation to shelter; improve, we can conclude that the project had relevance and • comparison with the condition of the adjacent was a reasonably good idea. But was this really the situation Amazon and Heracles mosaic; that needed improving? • a review of the literature on lift ing and citation While acknowledging that methods of lift ing and re-laying searches of the Orpheus publication; are still a challenge, we now recognize far more signifi cant chal- • professional input from colleagues involved in the lenges in conserving mosaics. In 1987, when the decision on the original project; project was made, the fi eld of mosaic conservation was on the • an analysis of the values of the Orpheus mosaic; and cusp of moving toward a much broader concept of conserva- • informal on-site assessment of the mosaic and shelter tion and the values attributed to archaeological sites. It is not over the years since implementation of the project. without some irony that the year aft er the Orpheus project was completed, the GCI organized the fi rst of its two international Th e remainder of this paper focuses on a selection of the courses on conservation and management of archaeological issues that emerged from the evaluation and were judged to be sites in Paphos, which encapsulated this larger vision. of most interest to and with broad implications for the mosaic Certainly today we would defi ne the “situation needing conservation fi eld. Th e review is structured according to the improvement”—at Paphos and indeed at most archaeological key evaluation questions. sites—very diff erently:

Relevance: Was the Project a Good Idea Given the • regular maintenance of sites; Situation Needing Improvement? • conservation and management planning for archaeo- How was the “situation needing improvement” defi ned eigh- logical sites; teen years ago? Th e issue was never made explicit in those TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 19 TJ14-3 P007-066 200L CTP.indd 19 3/3/08 11:21:59 AM Black

20 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

• a management structure responsive to the needs of (mainly those embedded in polyester resin aft er conservation; re-laying in 1989) (fi g. 5), as well as a few loose or • a better understanding of causes of deterioration to detached tesserae; mosaics left in situ in relation to treatment options; • continued erosion and exfoliation of the glass • trained and dedicated personnel to conserve, manage, tesserae; and monitor sites; and • detachment and extensive loss of the infi ll mortar in the • the continuing excavation of archaeological sites in large lacuna and around the edges of the mosaic; and the absence of all the above. • detachment of the new bedding: detachment occurred between the epoxy layer and the panel (not Th us we would have to acknowledge that the aims of where one might expect it, between the mortar and the project were soon made obsolete and are today not highly epoxy layers) and was documented over approxi- relevant given changed circumstances and approaches to mately one-fi ft h of the area of the mosaic but was par- conservation. ticularly noticeable in the southeast corner.8

Eff ectiveness: Have the Planned Results Been Achieved? With the exception of the loss of tesserae, these are cor- Were the Methods Used Eff ective? rectable problems. Certainly the overall good state of preser- Effectiveness can be measured in many ways, and we propose two ways for the Orpheus intervention: the effectiveness of the technique in preserving the materiality and the values of the mosaic. As an intervention, the rolling and re-laying procedure was complex, technically and logistically challenging, and risky. It was carried out with professionalism and skill, and it was largely successful inasmuch as it demonstrated that the tessellatum could be lift ed and relaid in its entirety, with relatively little loss or damage. Th is is not to suggest that there were no problems and diffi culties,5 but it is to recognize that the rolling proved an eff ective technique for lift ing a mosaic in one piece. But how eff ective was the intervention in preserving the material object (i.e., the relaid tessellatum) over time? To answer this question, an assessment of the physical condition of the mosaic was undertaken in 2004 by the authors of this paper.6 TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) Th e assessment was also an opportunity to determine whether documentation carried out during the project was adequate to permit a meaningful evaluation of the interventions to the mosaic fi ft een years later. In addition to rephotographing and recording the condition graphically, 7 we used the rapid assessment form developed for the initiative to assess the performance of shelters over mosaics (see Stewart, this volume). In summary, the survey revealed that aft er fi ft een years the Orpheus mosaic was in good condition. Th e most signifi cant deterioration that could be attributed to the years aft er the re-laying in 1989 were as follows:

FIGURE 5 Loss of tesserae that had been embedded in polyester • loss of tesserae: approximately seventy-fi ve tesserae resin soon aft er the re-laying; loss of infi ll mortar is visible on had been lost since 1989, most from border areas the right. Photo by Vassos Stylianou 2004. © J. Paul Getty Trust.

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The Project to Conserve the Orpheus Mosaic at Paphos 21

vation of the mosaic can be attributed to its isolation from the techniques and materials used (there was no documentation ground, but it is also important to remember that the mosaic available), and the many variables, it was not possible to make had been sheltered for the entire period of its relaid life. It is a meaningful comparison. It is of interest to note, however, diffi cult to assess the eff ectiveness of the re-laying on Aerolam® that many of the tesserae (red, blue-gray, and white limestone) panels as distinct from the protective function of the shelter.9 were actively fl aking, which was exacerbated by the infi ltration What is clear, however, is that the majority of post-1989 condi- of rootlets from vegetation that grew in the shallow covering tions can be attributed to lack of maintenance and monitoring (as micro-cracks developed in the tesserae, the rootlets pen- of the mosaic and the shelter, whose materials were allowed to etrated these). We believe this is the result of the very shallow degrade to a point where it was no longer serving a protective covering leading to wetting/drying cycles and perhaps salt function (fi g. 6). It should also be noted that despite a simple crystallization.10 barrier, there was no supervision of visitors, allowing direct A more challenging, less quantifi able measure of eff ec- access to the mosaic. All these conditions could have been tiveness is the success of the intervention in preserving the reversed or corrected had routine monitoring and mainte- values of the Orpheus mosaic. As noted earlier, aesthetic con- nance been undertaken. siderations were uppermost in the decision to use the rolling Th e Amazon and Heracles mosaic is located in the room technique to lift this fi gural mosaic. All methods of lift ing a adjacent to that of the Orpheus mosaic (see fi g. 1). It has had mosaic privilege certain artistic and historic values that reside a complicated life, with several episodes of excavation and in the tessellatum—such as artistic composition, iconography, reburial (beginning in 1942) and partial lift ing and re-laying and attribution to mosaic schools, makers, and patrons. Such in 1984. Since 1990 the mosaic had been protected, in a fashion information and appreciation, which is found in the surface of typical at the site, by a shallow covering consisting of green a mosaic (fi g. 7), can, however, also be gleaned from mosaics netting and a layer of sand (4–5 cm) and expanded clay pellets; removed to a museum. Th e decision to re-lay the mosaic in its the covering became shallower as the years passed. Th e assess- original location (rather than a museum) was a recognition ment of the Orpheus mosaic entailed a comparison of its con- that mosaics do indeed “make a site” and contribute signifi - dition with that of the Amazon and Heracles mosaic; and the cantly to the architectural ensemble of which they are a part. latter was uncovered and inspected for this purpose. However, Th ese are all critically important values to preserve, but due to uncertainty regarding its treatment history and the other aspects of the mosaic’s signifi cance have been lost through

FIGURE 6 Th e covering materials of the hexashelter had severely degraded by 2004, fi ft een years aft er the shelter was erected. Photo by Martha Demas 2004. © J. Paul Getty Trust. TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 21 TJ14-3 P007-066 200L CTP.indd 21 3/3/08 11:22:00 AM Cyan Magenta Yellow Black

22 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

to be better articulated, defended, and justifi ed in every intervention we make to a mosaic.

Impact: To What Extent Has the Project Contributed (Intentionally or Unintentionally) to Longer-Term Goals and Benefi ts to the Field? Impact is an especially important parameter in the fi eld of conservation, where fi nancial resources are limited. eTh Orpheus project was intended to have a larger impact on the fi eld. Paolo Mora’s message in the foreword to the 1991 publication expresses the intention:

While the rolling technique used for lift ing the Orpheus mosaic will not be applicable to all mosaics, and the cost or unavailability of specialized materials might be prohibitive in some cases, we consider it very important that conservators be made aware of this method. Increased familiarity with the technique will not only allow conservators to make more educated decisions in mosaics preservation, it may also serve as the basis for future developments and improvements in the technique. (Stanley-Price 1991: vi)

Despite the training component and the timely publication of the project, this intention of achieving wider impact FIGURE 7 Th e Orpheus mosaic aft er re-laying on its new support in 1989 (before infi lling lacunae) retains aspects of was not realized. A literature and citation search,11 and an artistic and historic value—artistic composition, iconography, assessment of unpublished practice to the extent that we know and attribution—that are most prized in mosaics. Photo by it, has not revealed any discernible infl uence on conservation Guillermo Aldana 1989. © J. Paul Getty Trust. thinking; on the use, development, or improvement of the rolling technique; or on the lift ing and re-laying of mosaics the lift ing and re-laying process. Th e historic and scientifi c generally. information that resided in the stratigraphy of the bedding lay- Th is, we believe, can be attributed to two factors. One is ers, including evidence of the preparatory design drawing and the technical and logistical diffi culties and cost implications TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) layout, was destroyed by this procedure. Th e stratigraphy was of this technique. Th e second, more important factor is the photographed and drawn, but other evidence was only noted changing approach to mosaic conservation (the trend toward and not otherwise documented. Whether such basic recording conservation in situ and a broader understanding of what conis suffi cient compensation for the loss of information is debat- servation entails), which was beginning to be felt just about able. Another aspect of historic value is the object as an authen- the time the project was undertaken. tic testament to its physical history—its patina of age. As has Nor did the project have any impact on the authori- been observed, however, one person’s patina is another’s dam- ties responsible for the site; indeed, an unintended conse- age (Muñoz Viñas 2005: 104), and this is well illustrated in the quence of the project may have been to encourage the notion diff ering opinions about the rigidity and extreme fl atness of the that because the mosaic was relaid on an isolating support, it relaid Orpheus mosaic—its appearance of having been ironed: required little or no maintenance. Certainly little was done some would argue that it helps reinstate the artistic signifi cance; over the fi ft een years to maintain or monitor the mosaic, its others, that it detracts from both its aesthetic and historic val- setting, and its shelter (fi g. 6). ues, especially in its ruined architectural context. Ultimately, And fi nally, there was no impact on the visiting public. this is a question of values—and a confl ict of values—that needs Th is is because the project had not been integrated into a

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The Project to Conserve the Orpheus Mosaic at Paphos 23

larger vision for the site. Th e result was a lost opportunity to of the mosaic and its protective shelter deteriorated due to the interpret the conservation intervention to the public. We have absence of eff ective management. One might argue that in the all experienced the fascination of the public with conservation face of ineff ective management and maintenance, the lift ing activities; if visitors can be engaged watching people clean a and re-laying proved a more sustainable result than conserv- mosaic, how much more engaged might they be by the rather ing the mosaic in situ, since it “hardened” the mosaic against dramatic story of the rolling and re-laying of the mosaic, and the vicissitudes of humans and nature. Th at may well be true, what more impressive didactic tool than the large wooden cyl- and there may be situations that require such an approach, but inder that lay just outside the shelter for thirteen years until it for a site of World Heritage stature, such as Paphos, sustain- was removed in the initial stage of landscaping the site? ability should be the result of good management rather than of fortifying a site against lack of management. Sustainability: Was the Project Design Adequate to Another important aspect of sustainability perti- Ensure a Sustainable Result? nent to conservation projects is documentation. Baseline Technical conservation solutions that do not take into account documentation is fundamental to assessing change in the the larger context in which they are being undertaken are future and determining whether deterioration is ongoing. ultimately not sustainable. For cultural heritage conservation, Documentation of the Orpheus mosaic was undertaken in context means the cultural context that contributes to signifi - 1988, 1989, and 2004 (fig. 8), but over the years condition cance; the management context in which the object is cared for terminology changed, technology evolved, grids shift ed, and and interpreted; and the physical and environmental context in cameras and lighting diff ered, making it diffi cult to replicate which the object exists. Th e only reasons to preserve a mosaic and be consistent. Nevertheless, baseline documentation of in its original location (rather than place it in a museum) are to the Orpheus mosaic was actually quite good, and the close- present it in a cultural context and, increasingly, to attract visi- up photography was especially useful for assessing change in tors, but in the absence of a management context that would surface conditions. But even the best documentation is use- ensure maintenance, protection, and interpretation, that pur- less if it is not properly archived, accessible, and used. Most pose is compromised, if not defeated. Th e Orpheus project project materials were archived, some were lost, not all the provided conservators with a technical solution for an object necessary documentation was provided to the partner insti- seen in isolation, but over the years the architectural setting tution, and what was provided could not always be found.

FIGURE 8 Graphic recording of the condition of the Orpheus mosaic in 2004, used for comparison with documentation undertaken in 1988 before re-laying and in 1989 aft er re-laying. Photo by Neville Agnew 2004. © J. Paul Getty Trust. TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 23 TJ14-3 P007-066 200L CTP.indd 23 3/3/08 11:22:05 AAMM Black

24 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

Although photodocumentation was well archived and cared tural sites. Orpheus and its shelter (and the adjacent Amazon for, it was never subsequently used or consulted, precisely and Heracles mosaic, with its few centimeters of protective because it was archival. A duplicate set of photographs was sand) hung on valiantly for fi ft een years waiting for such a never prepared in a form to be used (and accessed) by site solution12—permanent shelters and landscaping—and during personnel for future monitoring. this period, our values changed, the site deteriorated, documents were lost, personnel moved on, thousands of visitors came and went without being informed and educated, and Conclusion innumerable opportunities were lost for incremental change Th e answers to the evaluation questions do not tell us whether for the better. Surely, these are situations we can improve by the project aims were right or wrong, a success or a failure. taking them into account whenever we embark on a new proj- Th at is not the objective of evaluation. What is important are ect and must decide how to conserve and how best to use the the messages from the past that should inform our present and limited resources that are available to conservation. future actions. Th e results of the evaluation converge toward three key messages. Th e fi rst pertains to values and decision making. Values Notes

should be central to deciding whether to move a mosaic to a 1 Aerolam® panels are more commonly used for exhibiting detached museum (for exhibition or storage), lift and re-lay it in situ, mosaics in a museum, and rolling is generally done with smaller or conserve it in situ. Assessing values is not a purely subjec- cylinders; for a recent review of the history of lift ing and current tive undertaking, although it sometimes seems so; consensus trends, see Podany 2006: 115–28. among stakeholders matters, and it is the reason the fi eld of 2 Demetrios Michaelides, archaeological offi cer in Paphos at the mosaic conservation has moved toward in situ preservation. time. See Michaelides 1986 for discovery and excavation of the Nevertheless, whatever the conservation intervention, we need Orpheus mosaic. to be more eff ective at assessing and communicating those val- 3 For a journalistic overview of the need for a master plan at Paphos ues we are trying to preserve and what the implications of our and the origins of the World Bank project, see Wigg 1994: 1–24. intervention decisions are for signifi cance. While the primary For a more recent description of the plan, from the perspective response should be to seek solutions that preserve as many of of the Cypriot authorities, see Hadjisavvas 2003. the mosaic’s values as possible, the secondary response, when 4 For the IUCN methodology, part of its Global Monitoring and we destroy aspects of signifi cance, must be to compensate as Evaluation Initiative, see Woodhill 2000. Th e methodology was fully as possible for that loss, especially if the intervention, like selected based on research carried out by David Myers (project specialist, GCI). the Orpheus one, is irreversible. Th e second message concerns the importance of accu- 5 For example, shallow linear indentations in the tessellatum, rate, precise, and repeatable documentation that is archived seen only in raking light, are attributed to creasing of the plastic sheeting on which the tessellatum was unrolled, and there were and accessible. Accessibility is a function of how widely small areas of tesserae loss, most noticeably around the neck of TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) the documentation is published and disseminated and the the partridge. Th ese conditions were recorded by conservator medium in which it is recorded, especially for digital record- J. Claire Dean in a post-re-laying assessment.

ing. However, even if archived and accessible, documentation 6 Th e condition assessment was carried out September 4–11, 2004, will not be routinely used for monitoring unless it is spe- with the permission of the Department of Antiquities, Cyprus. In cifi cally tailored for that purpose. Th is requires monitoring addition to the authors of this paper, participants in the fi eldwork protocols that defi ne the indicators of change, such as photo- were conservator Andreas Georgiades and technician George graphs of specifi c conditions to be monitored over time, which Tapakoudes (Department of Antiquities) and Maria Ktori and Evi Charalambous, students from the Department of History are placed in the hands of those charged with using them. and Archaeology, University of Cyprus. Th e report on the field Undoubtedly the most important lesson to be learned assessment with recommendations was sent to the Department is that conservation interventions require eff ective manage- of Antiquities. ment (assessment and planning, trained personnel, a mainte- 7 Th e condition photography was undertaken by Vassos Stylianou nance regime, good leadership) if they are to be sustainable. using a Hasselblad camera fi tted with a digital back and followed Eff ective management demands holistic approaches but does the grid established for the 1989 photography. Giorgio Capriotti, not seek fi nal solutions; there is never a fi nal solution for cul- who had undertaken the original condition recording and

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The Project to Conserve the Orpheus Mosaic at Paphos 25

participated in the project in 1988–89, undertook the 2004 Agnew, N., S. Maekawa, R. Coff man, and J. Meyer. 1996. Evaluation recording with Th omas Roby. of the performance of a lightweight modular site shelter: Quantitative meteorological data and protective indices for the 8 We cannot be certain, however, that the detachment occurred in “hexashelter.” Conservation and Management of Archaeological the fi ft een years aft er re-laying. It may have been present in an Sites 1 (3): 139–50. incipient state upon re-laying in 1989. Hadjisavvas, S. 2003. Developing a World Heritage site: Th e case 9 See Agnew et al. 1996 for the eff ectiveness of the hexashelter of Paphos, Cyprus. In Mosaics Make a Site: Th e Conservation in prototype in modifying the environment under the shelter. Situ of Mosaics on Archaeological Sites: Proceedings of the VIth 10 Th e Amazon and Heracles mosaic was reburied by the Depart- Conference of the International Committee for the Conservation of ment of Antiquities aft er the 2004 assessment under a deep Mosaics, Nicosia, Cyprus, 1996, ed. D. Michaelides, 353–57. Rome: (50 cm) covering of soil. ICCM.

11 A literature search was undertaken through 2004 using the major Michaelides, D. 1986. A new Orpheus mosaic in Cyprus (Plates conservation databases (e.g., AATA, ArtIndex, BCIN, ICCROM LIII–LVI). In Acts of the International Archaeological Symposium library catalogue); citation searches were done in the Arts and “Cyprus between the Orient and the Occident,” Nicosia, 8–14 Humanities database and through the Web. Dissemination of September 1985, ed. V. Karageorghis, 473–89. Nicosia: Published the Orpheus publication was searched through Worldcat, which for the Republic of Cyprus by the Department of Antiquities, searches some 53,000 libraries in 96 countries, although the Cyprus. majority are in the United States; only 135 libraries contained the . 1991. Th e condition of the Orpheus mosaic following Orpheus mosaic. Th e authors are grateful to Valerie Greathouse excavation. In Th e Conservation of the Orpheus Mosaic at Paphos, (reference librarian, GCI) for undertaking the searches and Cyprus, ed. N. Stanley-Price, 11–12. Los Angeles: J. Paul Getty Sibylla Tringham (GCI graduate intern in 2004) for compiling the Trust. information. Muñoz Viñas, S. 2005. Contemporary Th eory of Conservation. Oxford: 12 Th e lightweight materials of the shelter (an impermeable Elsevier Butterworth-Heinemann. membrane and a permeable woven fabric) held up far beyond their intended life but were severely degraded by the time of the Podany, J. 2006. From fl oor to wall: Lift ing and exhibition practices assessment in September 2004. Th e Department of Antiquities applied to ancient fl oor mosaics. In Stories in Stone: Conserving attempted to repair the membrane in late 2004, but unsuccessfully, Mosaics of Roman Africa, ed. A. Ben Abed. Los Angeles: J. Paul as during winter storms in 2005 rainwater was observed falling Getty Museum and Getty Conservation Institute. on the mosaic and pooling. Th e membrane developed a large tear, Stanley-Price, N., ed. 1991. Th e Conservation of the Orpheus Mosaic at necessitating its removal in February 2006. Th e Orpheus mosaic Paphos, Cyprus. Los Angeles: J. Paul Getty Trust. has since been reburied, pending construction of the permanent shelters. Wigg, D. 1994. Of Mosaics and Mosques: A Look at the Campaign to Preserve Cultural Heritage. World Bank Development Essays 3. Washington, D.C.: World Bank.

References Woodhill, J. 2000. Introduction to key concepts, approaches and terms. Planning, Monitoring and Evaluating Programmes Agnew, N., and R. Coff man. 1991. Development and evaluation of the and Projects, Working Draft . Version 1—March 2000. hexashelter. In Th e Conservation of the Orpheus Mosaic at Paphos, Global Monitoring and Evaluation Initiative, IUCN (World Cyprus, ed. N. Stanley-Price, 36–41. Los Angeles: J. Paul Getty Conservation Union). www.iucn.org/themes/eval/documents2/ Trust. pme_concepts/pme_concepts_terms_00.pdf. TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 25 TJ14-3 P007-066 200L CTP.indd 25 3/3/08 11:22:12 AM Black

Bilan d’opérations réalisées par l’ Atelier de Saint-Romain-en-Gal

Évelyne Chantriaux, Marion Hayes, Christophe Laporte, Andréas Phoungas et Maurice Simon

Résumé : Le thème de cette 9e conférence générale, et cette de maintenance, permettront de préciser le rôle et la part de année 2005, qui marque pour l’Atelier de Saint-Romain-en-Gal responsabilité des diff érents acteurs de la conservation. 25 ans de fonctionnement, fournissent l’occasion de dresser des Par ailleurs, le bilan de certaines opérations particu- bilans et de s’interroger : que sont devenues les mosaïques que lières liées à des contextes archéologiques peut donner lieu nous avons traitées ? Et comment juger aujourd’hui certaines à une évaluation critique : en faisant apparaître la position opérations qui ont suscité des controverses ? Cet exposé se pro- de l’atelier par rapport aux demandes des commanditaires et pose de présenter un tableau des interventions réalisées depuis des instances décisionnelles, puis en précisant la nature des 1980, en développant quelques cas spécifi ques, choisis pour les interventions matériellement réalisées et en concluant par le constats et les enseignements qui peuvent en être tirés. constat que l’on peut aujourd’hui établir, avec le recul d’une ou deux décennies. Abstract: Th e theme of this 9th conference and the year 2005, which marks twenty-fi ve years of work for the Saint-Romain- Bilan des opérations réalisées depuis 1980 en-Gal workshop, provide an opportunity for evaluation and posing some questions: What has become of the mosaics we have L’atelier est intervenu sur plus de deux cents pavements tota- treated? How can some of the controversial operations under- lisant près de 3 000 m2. La surface globale est essentiellement taken in the past be judged today? Th is presentation seeks to composée de mosaïques, les autres pavements tels que opus review the interventions carried out since 1980, going into detail sectile, sols de terrazzo-signinum et dallages divers représen- with a few specifi c cases chosen for the fi ndings and the lessons tant un peu plus de 5 % de la totalité. Le tiers de ces opérations TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) that can be learned from them. correspond à des interventions in situ d’études diagnostiques, de nettoyages, de consolidations (fi g. 1), et d’établissement de Le thème proposé pour cette 9e conférence de l’ICCM fournit documentation descriptive, graphique et photographique. Les l’occasion de dresser un bilan des travaux réalisés par l’atelier 2 000 m2 restants se répartissent en 1 300 m2 restaurés – dont depuis sa création en 1980. Le propos n’est pas de mettre l’ac- 900 m2 issus de déposes réalisées par l’atelier – et 700 m2 cent sur les quantités traitées au cours de ces vingt-cinq ans, déposés qui n’ont pas fait l’objet d’une restauration. mais de s’intéresser à l’état actuel des mosaïques sur lesquelles Sur l’ensemble des restaurations qui concerne cent l’atelier est intervenu et de s’interroger : que sont devenues les vingt pavements, le tiers correspond à des reprises de restau- 1600 m2 de surfaces déposées ? Dans quelle mesure sont-elles rations anciennes ou récentes. Ces mosaïques scellées sur des accessibles aux chercheurs ou au public ? Quelle fraction reste supports de ciment, de plâtre ou de résine – près d’une cin- exploitable, et à quelles conditions ? Quelle appréciation peut quantaine totalisant une surface de plus de 400 m2 – posaient être faite des 1 300 m2 de mosaïques restaurées, présentées en des problèmes de conservation ou de présentation qui ont musée ou in situ ? Ces questions, qui ramènent aux notions entraîné leur remontage sur des supports de nid d’abeille et récurrentes de documentation, de conservation préventive et une remise en valeur de leur état de surface ; citons à titre

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Opérations réalisées par l’atelier de Saint-Romain-en-Gal 27

mosaïques, ou les ensembles de plusieurs pavements, pour lesquels la lourdeur des dispositifs à mettre en place en vue de leur présentation constitue un obstacle : ainsi certains musées saturés ne permettent pas de les intégrer, comme à Aix-en-Provence, où les découvertes archéologiques des trente dernières années restent en réserves. Dans ce cas, le projet d’une vaste exposition temporaire initié par le service archéologique municipal pourra peut-être convaincre les autorités locales de la nécessité de créer un lieu de présen- tation. Ailleurs, ce sont les aléas politiques qui empêchent l’émergence d’un musée, comme à Saint-Paul-Trois-Châteaux où le changement de municipalité a entraîné l’abandon du projet mené par l’équipe précédente. Ou c’est la complexité des problèmes à régler qui est en cause, dans les cas de repo- FIGURE 1 Consolidation d’une mosaïque conservée in situ sur ses in situ notamment, comme à Saint-André-de-Rosans, où le site de Plassac (Gironde). Cliché : atelier. la réintégration des mosaïques à leur emplacement d’origine suppose la restauration des vestiges du prieuré dont elles proviennent, l’édifi cation d’une structure de protection et la d’exemple la reprise du traitement de la mosaïque funéraire programmation de mesures d’entretien. de Pelagius (Tabarka, Tunisie) (Chantriaux et al. 1994) , incor- Le tiers restant regroupe les mosaïques pour lesquelles rectement reconstituée en 1884 après avoir été brisée lors de des solutions autres que la présentation intégrale en musée son transport au Musée du Louvre (fig. 2, 3). Au vu des dif- ou le statu quo ont été trouvées. Certaines mosaïques sont fi cultés et de la lourdeur de certaines de ces opérations, le premier constat peut être de rappeler l’importance de bien mesurer l’in- cidence du choix des techniques et des maté- riaux sur le devenir des mosaïques traitées ; ce qui revient à souligner l’importance de respecter la règle de la réversibilité dans les interventions aujourd’hui mises en œuvre. La situation des mosaïques restaurées est variable. Plus de la moitié est exposée en musée (fi g. 4), ou en attente de l’être dans des salles en cours de création ou de réamé- nagement, mais une fraction non négligea- ble reste inaccessible. Près du cinquième des mosaïques traitées n’ont en eff et pas encore trouvé d’emplacement pour leur exposition au public. L’absence de lieux de présentation peut traduire une insuffi sance de moyens, quand il existe une disproportion entre la richesse des collections archéologiques et la taille de certaines petites communes, ou une absence de volonté commune de la part des instances concernées : collectivités, services FIGURE 2 Mosaïque funéraire de Pelagius FIGURE 3 État après la restauration eff ectuée patrimoniaux, associations locales. Ce type (Tabarka, Tunisie) ; démontage de la restau- en 1993 pour le Musée du Louvre. Cliché : de situation concerne surtout les grandes ration datant de 1884. Cliché : Paul Veysseyre. Paul Veysseyre. TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 27 TJ14-3 P007-066 200L CTP.indd 27 3/3/08 11:22:13 AAMM Cyan Magenta Yellow Black

28 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

tenant à la mosaïque des Auteurs grecs d’Autun2, restauré dès après sa découverte à l’état de fragments en 1990 (fig. 5, 6). D’autres attendent plus longtemps la programmation de leur traitement. La majorité des déposes, eff ectuées dans le cadre de fouilles de sauvetage (fi g. 7), permettent en eff et de sauve- garder le moindre vestige de pavement découvert. Mais si aucune sélection ne s’applique à ce stade, ce qui – il faut le souligner – constitue une réalité qu’il convient d’apprécier à sa juste valeur, les commandes de restauration ne suivent pas systématiquement. Dans le cas d’ensembles importants, le choix des mosaïques destinées à être présentées, donc à res- taurer, se porte en priorité sur les pavements les plus remar- quables, délaissant les pavements les plus « ingrats », parce que trop fragmentaires, ou redondants dans des séries déjà FIGURE 4 Mosaïque de l’Enlèvement d’Hylas (dépôt de la ville bien représentées ; le tri s’impose alors pour des raisons de de Grenoble) présentée au Musée de Saint-Romain-en-Gal. saturation des espaces de présentation, ou par limitation des Cliché : Paul Veysseyre. sources de fi nancement, parfois aff ectées à d’autres objectifs, culturels ou non, en tout cas plus médiatiques. Ce type de situation conduit d’ailleurs au constat qu’une nouvelle poli- ainsi présentées partiellement, faute de place suffi sante pour les tique de conservation des vestiges se met en place, qui limite exposer entièrement, ce qui évidemment constitue un pis-aller, les fouilles à des sondages d’évaluations et s’accompagne du mais sans doute préférable à l’oubli total au fond d’une réserve. réenfouissement des pavements repérés. Quelques pavements sont présentés dans des lieux autres que Il n’empêche que toutes les mosaïques déposées consti- sites et musées ; il s’agit le plus souvent d’espaces publics : mai- tuent des témoins d’histoire. Même non restaurées, elles ries, offi ces de tourisme, qui suppléent l’absence de musées et représentent un fonds répertorié et documenté, accessible évitent la dispersion du patrimoine local. Une autre partie des aux chercheurs. Et elles restent potentiellement exploita- mosaïques est présentée dans le cadre d’expositions temporai- bles à des fins de restauration et de présentation, si les res, et conservée en réserve le reste du temps ; à Saint-Romain- conditions de leur stockage assurent leur préservation. On en-Gal, les mosaïques entreposées dans la réserve équipée de peut citer à titre d’exemples la mosaïque de Passins (Isère), châssis coulissants restent accessibles sur demande aux pro- déposée en 1983 et restaurée vingt ans plus tard3 (Lavagne fessionnels, et au public dans le cadre de visites spécifi ques 2000) ; ou une mosaïque à décor géométrique prélevée en donnant accès aux « coulisses » du musée. Le dernier groupe 1876 lors de travaux de terrassement pour la construction TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) correspond aux mosaïques reposées in situ, de manière per- d’une ligne de chemin de fer à Sainte-Colombe-lès-Vienne, manente ou saisonnière, comme à Saint-Romain-en-Gal selon restaurée cent vingt ans plus tard. À l’inverse, certaines le système d’exposition estivale présenté à la conférence de mosaïques récemment déposées ont été endommagées à des Th essalonique (Chantriaux et al. 1994). degrés divers par suite de négligences, alors qu’elles avaient été laissées par l’atelier dans un parfait état de conservation : déformées et fragmentées après avoir été démunies Bilan des opérations de dépose de leur support de contreplaqué, leur entoilage moisi pour Si l’on observe maintenant le bilan des opérations de dépose, avoir été stockées en extérieur, exposées aux intempéries, le constat est plutôt positif puisque 900 m2 ont été restau- ou encore la moitié des tesselles détachées à la suite d’un rés et présentés pour la plupart au public sur les 1 619 m2 transport vertical. Le constat, amer, serait dans ce cas d’in- déposés. Certaines restaurations suivent immédiatement tervenir dans le cadre des formations en conservation pré- le prélèvement, comme la mosaïque de Méduse découverte ventive organisées dans divers cadres institutionnels de à Besançon1 en 2004, restaurée en 2005 pour une exposi- manière à rappeler les règles de base du stockage et du tion prévue en 2006 ; ou le panneau de Métrodore appar- transport des mosaïques.

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Opérations réalisées par l’atelier de Saint-Romain-en-Gal 29

FIGURE 5 Fragments du panneau de Métrodore à leur découverte en 1990 à Autun FIGURE 6 Détail du panneau après sa restauration en (Saône et Loire). Cliché : atelier. 1992. Cliché : Paul Veysseyre.

Cas particuliers Une autre opération a permis de retrouver le même Parmi les déposes et les interventions eff ectuées sur des mosaï- architecte pour le traitement de la mosaïque romane du déam- ques conservées in situ, quelques opérations se distinguent par bulatoire de l’église St-Philibert de Tournus5. Dans ce cas, le les controverses qu’elles ont suscitées. Les déposes sont en eff et confl it ne concernait pas la dépose, l’état du pavement auto- réalisées quand elles sont justifi ées par une nécessité de sauve- risant sans conteste son maintien in situ, mais portait sur les garde ; mais l’atelier a refusé d’en exécuter certaines. Un pre- choix de mise en valeur. En premier lieu, l’architecte a décidé mier exemple concerne la mosaïque médiévale de l’église de de limiter la présentation à la partie la mieux conservée de la Cruas4 (Ardèche) ; dans ce cas, la dépose initialement prévue à mosaïque, alors qu’un collège de conservateurs, d’historiens, des fi ns de remontage sur un nouveau support a été remplacée de chercheurs – auxquels l’atelier s’est associé – défendait le par une consolidation in situ, après que l’atelier ait diagnos- projet d’une présentation exhaustive de l’ensemble du pave- tiqué un état de conservation qui permettait de maintenir la ment. Malgré l’argumentation développée autour du carac- mosaïque sur son mortier d’origine. Quinze ans après l’opéra- tère réducteur de ce choix, l’architecte a maintenu son projet tion, la mosaïque ne présente aucun signe d’altération. et les ⅔ du pavement, conservés dans un état fragmentaire, Dans un autre cas, celui d’un dallage médiéval en car- ont été réenfouis après consolidation. reaux de terre cuite conservé dans la basilique Notre-Dame de Une deuxième polémique, cette fois à l’instigation de Paray-le-Monial (Saône-et-Loire), l’architecte des Monuments l’atelier, s’est déclarée, à l’issue des opérations de consoli- Historiques demandait une dépose partielle des parties les dation et de nettoyage, à propos du traitement des lacunes. mieux conservées, sans fi nalité de sauvegarde puisque le L’architecte souhaitait un comblement uniforme de toutes les réenfouissement du carrelage devait en assurer la conserva- parties de tessellatum disparues – avec restitution du tracé de tion, et alors même que les archéologues avaient mené leur la composition géométrique –, ce qui impliquait de détruire fouille de manière à éviter les zones dallées. L’atelier a refusé les réparations en mortier de tuileau eff ectuées pendant le d’intervenir, mais le prélèvement a quand même été réalisé, temps d’usage du pavement, et de recouvrir les couches supé- par un autre restaurateur. rieures du support d’origine, conservées par endroits (fig. 8). TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 29 TJ14-3 P007-066 200L CTP.indd 29 3/3/08 11:22:18 AM Cyan Magenta Yellow Black

30 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

contestable, l’atelier effectue – sans facturation – toutes les déposes demandées par le service régional de l’archéologie dans le Rhône et en Isère, les deux départements fondateurs et gestionnaires de notre structure. Dans le cas du baptistère de Grenoble, découvert Place Notre-Dame en 19896 à l’occasion du chantier du tramway, les archéologues souhaitaient effectuer une fouille sous le dallage conservé autour de la cuve baptismale, ce qui imposait de le déposer. Ce dallage, conservé sur une trentaine de m2, est constitué d’une partie centrale en dalles de calcaires ocre et rose, encadrée par des blocs de brèche rouge et de poudingue gris dans les quatre absides. Son état de conservation aurait permis de le consolider in situ, au même titre que la cuve baptismale qui, elle, est restée en place. L’atelier a donc proposé que les fouilles soient limitées aux parties lacunaires du pavement, puis a essayé de limiter l’intervention à une dépose partielle, mais a finalement dû s’exécuter et réaliser le prélèvement total de cet ensemble monumental, avec l’objectif de reposer le dallage dans l’exacte configuration qu’il présentait à sa découverte. L’opération a été lourde, dans tous les sens du terme, et s’est échelonnée sur six années. La dépose a été eff ectuée en 1992, après la réalisation d’une empreinte de toute la surface, avec un système de mousse de polyuréthane coulée dans un coff rage de bois établi selon un niveau de référence parfaite- ment plan. Ces contreformes ont permis de réaliser, au dos des éléments du dallage, des coques en résine époxy armée FIGURE 7 Dépose d’une mosaïque à Orange (Vaucluse) de fi bres et de toile de verre, avec un repérage, en près de 300 en 1990. Cliché : atelier. points, de toutes les dénivellations du revers. L’ensemble, coques et dalles de pierre, a ensuite été reposé dans le bap- L’application systématique d’un enduit moderne aurait par tistère avec un système de tiges fi letées réglées en chaque ailleurs masqué certaines marques de facture – des limi- point relevé, de manière à restituer les niveaux d’origine. tes de reprise de travail notamment – et fait disparaître les Seule l’une des absides a été remontée sur un support plan TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) zones de tessellatum érodées qu’il était également question en vue de son accessibilité au public. Le bilan de l’opéra- de recouvrir. Diplomatiquement géré par la Direction des tion, à son achèvement en été 1998, a été celui d’une réussite services municipaux, qui – par chance – suivait scrupuleu- technique, avec l’amertume d’avoir dû céder à d’autres exi- sement le déroulement des opérations et a bien voulu consi- gences que celles dictées par des objectifs de conservation. dérer le point de vue de l’atelier, le désaccord s’est soldé par Mais il a évolué depuis. Des problèmes de développement une intervention minimale, limitée au comblement des lacu- de micro-organismes sont en eff et apparus par la suite dans nes profondes et des zones fragiles par un enduit de chaux la crypte aménagée pour la présentation du baptistère et de chargé de tuileau. son contexte archéologique. Seul le dallage, isolé par ses L’atelier n’a pas toujours eu gain de cause, et le der- coques synthétiques est resté intact, ce qui oblige à réviser le nier cas présenté concerne une opération que nous avons constat initial, en reconnaissant que fi nalement, la dépose et réalisée contre notre volonté. Précisons que s’il nous est le remontage sur un nouveau support se sont avérés justifi és, possible de refuser certaines opérations dont la nature est a posteriori.

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Opérations réalisées par l’atelier de Saint-Romain-en-Gal 31

FIGURE 8 La mosaïque médiévale de l’église Saint-Philibert de Tournus (Saône et Loire) lors de sa découverte en 2002. Cliché : Paul Veysseyre.

Conclusion Notes

La conclusion de cet exposé pourrait être de présenter le 1 Fouille du Collège Lumière réalisée à Besançon (Doubs) en 2004 bilan des essais de vieillissement mis en place en 1990 pour la par l’INRAP (Institut national de recherches archéologiques conférence de Palencia (Chantriaux et al. 2005). En réalité, le préventives) sous la direction de Claudine Munier. constat de cette expérimentation ne peut être développé pour 2 Fouille réalisée rue de la Grille à Autun en 1990 sous la direction diverses raisons : par manque de temps pour s’attacher à sui- de Pascale Chardron-Picault, archéologue municipale. Voir le vre régulièrement l’évolution des échantillons de mosaïque Catalogue de l’exposition : Musée Rolin. 1992. Métrodore : un placés en examen, mais surtout par manque de conviction sur philosophe, une mosaïque. Autun : Musée Rolin. la portée des résultats recueillis, à savoir que les mosaïques se 3 Fouille réalisée en 1981 à Passins (Isère), sous la direction de dégradent quand elles ne sont pas protégées ! L’opération a été Michel Colardelle (Centre archéologique de l’Isère). engagée avec l’intention louable d’apporter une contribution 4 Campagnes de fouilles de sauvetage menées de 1983 à 1988 par à la conservation in situ des mosaïques. Mais l’ensemble se Joëlle Tardieu (Service régional de l’archéologie). Travaux de comporte comme une unité dont les variations constatées restauration de l’église réalisés en 1989 et 1990 sous la direction ne seraient sans doute pas d’une grande utilité pour être de Francesco Flavigny, architecte en chef des Monuments Historiques. exploitables dans d’autres conditions. Ainsi, pour conclure cette présentation de bilans, la seule règle absolue dans notre 5 Fouille réalisée en 2002 sous la direction de Benjamin Saint- domaine d’intervention, comme l’a écrit René Huyghe (1950 : Jean Vitus (INRAP). Travaux de restauration réalisés en 2001 et 2002 sous la direction de Frédéric Didier, architecte en chef des

199) à propos de la restauration des peintures, est « qu’il Monuments Historiques. Voir C. Sapin, ed., Le décor retrouvé à n’existe que des cas d’espèces ». Saint-Philibert de Tournus : Regards sur la mosaïque médiévale. Tournus 18 et 19 sept. 2003. Tournus : C.I.E.R., 2004.

6 Fouille réalisée de 1990 à 1992 sous la direction de François Baucheron (Direction des Antiquités historiques de la région Rhône-Alpes). Travaux d’aménagement de la crypte archéologique réalisés de 1992 à 1998 sous la direction de François Botton, architecte en chef des Monuments Historiques. TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 31 TJ14-3 P007-066 200L CTP.indd 31 3/3/08 11:22:27 AAMM Black

32 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

Presentation : Th essaloniki, 29 October–3 November 2002 : Références Proceedings, ed. Ch. Bakirtzis. Th essalonique : European Center Chantriaux, É., et al. 1994. Conservation report of the mosaic of of Byzantine and Post-Byzantine Monuments. Tabarka by the Atelier de restauration de mosaïques of Saint- Chantriaux-Vicard, É., C. Laporte, M. Hayes et A. Phoungas. 1994. Romain-en-Gal. In From Hannibal to Saint Augustine : Ancient Éléments de recherche pour une contribution à la conservation Art of North Africa from the Musée du Louvre, ed. M. Seefried des mosaïques in situ. Dans Mosaicos, no. 5 : Conservación Brouillet and F. Baratte, 139–41. Atlanta, Ga. : Michael C. in situ : Palencia, 1990 : IV Conferencia general del Comité Carlos Museum. internacional de mosaicos, ed. ICCM and ICCROM, 139–49. . 2005. Maintenance et présentation in situ à Saint- Palencia : Excma. Diputación Provincial, Departamento de Romain-en-Gal. Dans 8o Synedrio Diethnous Epitropes gia te Cultura. Synterese ton Psephidoton (ICCM) : Entoichia kai epidapedia Huyghe, R. 1950. Museum 3 (3) : 199. psephidota : Synterese, diaterese, parousiase : Th essalonike, 29 Oktovriou–3 Noemvriou 2002 : Praktika = VIIIth Conference Lavagne, H. 2000. Recueil général des mosaïques de la Gaule, III, of the International Committee for the Conservation of Mosaics Narbonnaise, 3. Paris : CNRS. (ICCM) : Wall and Floor Mosaics : Conservation, Maintenance, TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S)

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Learning from the Literature: A Review of Published Works on Mosaic Deterioration and Conservation Treatments

Francesca Piqué, Rachel Burch, Thomas Roby, and Martha Demas

Abstract: Th is paper summarizes the review of the literature of the causes of deterioration of in situ mosaic pavements on causes of deterioration, treatment, and maintenance under- and developing strategies and methods for their preservation taken as part of the Getty Conservation Institute’s Mosaics in (Demas 2003). A review of literature concerning the con- Situ project. Th e literature review indicates progressive develop- servation of mosaics was begun with the primary objective ments in methods and approaches to the preservation of mosaic of informing and guiding the research, testing, and training pavements on archaeological sites over the past four decades. It components of the project. As the review progressed, it was reveals also, however, that the understanding of mechanisms of considered a useful resource to the mosaic conservation fi eld deterioration remains largely intuitive, with a signifi cant lack of as a whole.1 diagnostic studies. Treatments are rarely developed in response Categories were established to refl ect the principal issues to specifi c deterioration or diagnostic investigations, and there is related to mosaic conservation: deterioration; treatment and little evaluation of their effi cacy over time. However, interven- maintenance; reburial; sheltering; mosaic inventories and tions are increasingly emphasizing the use of compatible (lime- corpora; and training. A critical review was written for each based) materials, with a focus on preventive preservation and category in order to establish the current state of knowledge regular maintenance of mosaics in situ. and identify areas in need of further research. Th is paper summarizes the review of the literature on causes of deterioration Résumé : Cette communication résume la documentation étudiée and on treatment and maintenance. While we recognize that dans le cadre du projet sur les mosaïques in situ de l’Institut Getty the published literature will never mirror exactly the reality de Conservation sur les causes de détérioration, les traitements et of current practice and that many conservation projects and l’entretien. La revue évoque l’évolution des méthodes et des appro- some research initiatives remain unpublished, we believe that ches concernant la préservation des pavements en mosaïques sur a review of the literature is nevertheless a valid refl ection of les sites archéologiques depuis quarante ans. Elle constate que les the current state of the fi eld. A critical review of the literature connaissances sur les mécanismes de détérioration demeurent through 1988 was published in 1994 (Nardi 1994a); the present intuitives et que les études diagnostiques sont rares. Les traite- literature review includes that material plus the literature that ments sont rarement conçus pour répondre à une détérioration has been published since (1989–2005). spécifi que ou à des investigations diagnostiques et leur effi cacité Published works on mosaics were searched on several dans le temps est rarement évaluée. Les interventions soulignent Web-based reference databases.2 Th ose that provided the de plus en plus l’utilisation de matériaux compatibles (à base de most information were the Bibliographic Database of the chaux), et insistent sur la préservation préventive et l’entretien Conservation Information Network (BCIN); AATA Online: régulier des mosaïques in situ. Abstracts of International Conservation Literature; the ICCROM library catalog; and SciFinder®, a subscription-based Th e Getty Conservation Institute’s Mosaics in Situ project was research interface that allows access to Chemical Abstracts, a initiated in 1997, with the aim of improving understanding large collection of scientifi c publications. Th is search, limited

33 TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 33 TJ14-3 P007-066 200L CTP.indd 33 3/3/08 11:22:30 AM Black

34 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

to articles in English, Italian, Spanish, French, and German, Diff erent foundation layers and variations in the diff erent produced over a thousand references, which were organized chemical and physical properties of their constituent materials according to the subject categories listed above.3 Th e digi- can result in variable types of deterioration (under the same tal record of the references was compiled using the refer- conditions). ence management soft ware ProCite®. Th e largest group of Explicit correlation between the chemical-physical references reviewed was published in the proceedings of the nature of material components and their deterioration can be International Committee for the Conservation of Mosaics found in very few publications. Examples of work in which (ICCM); another main source was the biennial proceedings this correlation is made are mosaics from Th ebes, Greece, of the Associazione Italiana per lo Studio e la Conservazione where the low binder (lime) to fi ller (sand) ratio in the mor- del Mosaico (AISCOM; Italian Association for the Study and tars is reported as one of the causes of their deterioration Conservation of Mosaics) and other recent Italian conference (Karatasios, Watt, and Colston 2003: 125); and the friable mor- proceedings. Most of the remaining references were found as tar layer rich in ashes and charcoal at the site of Horvat Minim individual papers in the more general conservation literature. in Israel which is preferentially penetrated by plant roots Only one small book devoted specifi cally to mosaic conserva- (Neguer 2004: 251). Similarly, the mineralogical nature of the tion (materials and techniques for treatment) was found for tesserae has been used to explain preferential deterioration inclusion in the review (Fiori and Vandini 2002). (Lopreato, Fiori, and Perpignani 2003: 185–86 [ceramic tesserae]; Menicou, Fiori, and Macchiarola 2003: 228; García del Cura et al. 1992; Aoyagi and Foschi 1997: 820) and preferential Causes of Deterioration as Discussed in the biological attack (Altieri, Poggi, and Ricci 2003: 254; Lazzarini Published Literature et al. 2004: 397). Th e review has been divided into four categories that relate to Preferential colonization of more porous substrates by causes of deterioration occurring in the “life cycle” of a mosaic, algae has been quantitatively demonstrated (McStay et al. from its construction, through abandonment, reburial, and 2001: 381). Th ere is also a small corpus of articles presenting excavation, up to its present condition: scientifi c studies characterizing stone (Bergamini and Fiori 1999) and glass tesserae (Verità 2000: 72; Fiori, Lorusso, and 1. Intrinsic qualities: deterioration engendered by Vandini 2000: 23), but rarely are the studies related to causes original construction technique and original choice of deterioration or to selection of treatment materials and of materials methods. 2. Historic events: deterioration engendered by aban- Th e foundations of a mosaic play an important role donment, burial, and excavation in its long-term stability, and there are several examples of 3. Environmental impact: deterioration engendered by the diff erential settling of mosaics attributed to underlying exposure to the environment archaeological features such as hypocausts, walls, or earlier 4. Human action: deterioration engendered by modern hearths (Neal 1997; Michaelides 1991: 11; Novis 1985: 104); or to TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) interventions and mismanagement the original construction of the fl oor itself (Chlouveraki and Politis 2003: 150). Th is categorization is far from perfect given the overlap and interrelationship of the causes of deterioration in diff erent Historic Events moments of the life cycle of a mosaic. However, it highlights Th is category includes deterioration during abandonment and and distinguishes deterioration factors that cannot be pre- collapse or destruction, gradual natural burial, and archaeo- vented (i.e., intrinsic factors and historic events) and those logical excavation. that can be improved through better research and manage- It is diffi cult, perhaps impossible in most instances, to ment (i.e., environmental and human factors). identify when damage visible today has occurred to a mosaic. For example, many articles describe the problem of deforma- Intrinsic Qualities tion of the tessellatum, but it is seldom evaluated in terms of Mosaics are composed of foundation layers of diverse types when and how damage occurred. Evidence of damage caused of mortars and a surface of tesserae generally made of sev- during the initial destruction or abandonment of a site is sug- eral types of stone and, less frequently, of ceramic and glass. gested in a few examples, such as subsidence of the mosaic and

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Learning from the Literature 35

presence of lacunae attributed to the impact of architectural take place (García del Cura et al. 1992: 473; Costanzi Cobau elements at the time of collapse due to seismic activity (e.g., 1990: 130). A few articles address methods of excavation and Gambogi, Fontanelli, and Tuccino 1998: 154; Chmielewski the mitigation of damage during excavation (Roby 1995; Nardi 2005: 149). 2004: 147); and there have been calls to halt or minimize exca- Once in their buried state, mosaics may be considered to vation until training of conservators specialized in conserva- exist in a stable environment where deterioration is very slow tion in situ is possible (see, e.g., Al-Azm 2004: 200). Despite compared to an exposed situation (Sease 2003: 69). However, the general awareness of the negative eff ects of excavation on various types of deterioration can occur to buried mosaics mosaics, actual examples of deterioration of a mosaic during (summarized in Stewart 2004: 238–43). Mechanical deforma- or immediately aft er excavation are not frequently reported tion of the tessellatum, caused by diff erential resistance of in the literature. A dramatic example is the rapid bulging and constituent layers (tessellatum, bedding layer, nucleus, rudus, detachment of the tessellatum of a mosaic at the site of Tel and statumen) to lateral and perpendicular forces may also Itztaba in Israel soon aft er excavation (Neguer 2003: 204). occur during burial, and stresses exerted by overburden and One of the earliest and continuing concerns in the surrounding structures or later rebuilding causing deforma- published literature was damage to sites from development tions such as bulging, sinking, and cracking have been much and building construction (Bassier 1978: 68; Nardi 1986: 96; reported (Bassier 1978: 69; Chantriaux-Vicard 1990: 294; Gambogi, Fontanelli, and Tuccino 1998: 153; Karivieri 2005: Cenciaioli et al. 1998: 179; Roby 1995: 51; Manconi and Scaleggi 193), and both accidental discoveries and construction and 1995: 115). redevelopment can cause considerable and irreversible dam- Th e chemical composition of archaeological depos- age to mosaics. Th e literature confi rms the problem is ongo- its has been reported to potentially aff ect the condition of a ing. Accidental discovery and damage by activities such as mosaic (Mingarro Martín and López de Azcona 1986). It has plowing are reported (Bassier 1978: 68; Aoyagi and Foschi been shown that the nature of the soil, in particular its pH, 1997: 819; Neal 1997: 18; Foschi 2000: 720). Although the lit- and microorganisms present in the soil can aff ect the pre- erature indicates a move away from wholesale detachment dominantly calcareous mosaic components as well as other of mosaics, dramatic large-scale detachments of mosaics still pH-sensitive materials such as glass tesserae (Fernandez 1987: periodically occur, notably, the recent examples of the redevel- 284; Chantriaux-Vicard 1990: 295; Lazzarini et al. 2004: 397). opment of the Central District of Beirut, which included the A few authors have emphasized the potential negative role lift ing of more than 700 square meters of Roman-Byzantine of agricultural chemicals on mosaics, notably, by produc- mosaics over several years starting in 1993 (Skaf and Roby ing free potassium, nitrate, and phosphate ions (Aoyagi and 2003: 221–28) and the emergency work at Zeugma in Turkey in Foschi 1997: 819; Weidmann 1987: 13; Fernandez 1987: 284; advance of fl ooding of the ancient city by a reservoir in 2000 Foschi 2000: 720); and in the formation of insoluble salt crusts (Nardi and Schneider 2004). (Chantriaux-Vicard 1990: 286). Even planned and professional archaeological excava- Environmental Impact tions are acknowledged to cause immediate damage and also Following the unearthing of a mosaic, many causes of dete- to set up conditions for future deterioration, and over the past rioration from the environment (e.g., water and salts, thermal twenty years the literature has refl ected the conservation com- variation, and biological factors) come into play. Water and munity’s concern with excavation methods and the impor- salts are the most frequently mentioned factors. Salt effl o- tance of conservators’ involvement in archaeological activities rescence on the surface of a mosaic is a phenomenon oft en (Costanzi Cobau 1990: 130; Muceli 2004: 357)—indeed, that reported in the literature, and salts in association with water conservation should be an acknowledged part of the archae- are commonly identifi ed as causing mechanical disruption of ological process (de la Torre, comment in Sease 2003: 77). the porous materials making up mosaics (Mingarro Martín Upon excavation, the mosaic is suddenly exposed to abrupt 1989: 28; Abd El-Hady 1990: 33–35; Cosh 2002: 4; Edwards et changes of environmental conditions, which bring about rapid al. 2003: 103; Cenciaioli, Botti, and Scaleggi 1998: 178; Menicou, responses that oft en result in deterioration (Chantriaux-Vicard Fiori, and Macchiarola 2003: 228; Yiannouli, Anastasatou, and 1990: 296; Sease 2003: 69). Th e tessellatum becomes the inter- Papastamatiou 2003: 55; Fiori 2004: 11). face between atmosphere and soil, where damaging processes, Th e source and nature of salts, the mechanism for such as crystallization of salts and biological colonization, their movements and crystallization, and their role in the TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 35 TJ14-3 P007-066 200L CTP.indd 35 3/3/08 11:22:31 AM Black

36 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

disaggregation, exfoliation, and fracturing of tesserae, and change the physical (notably, porosity) and chemical charac- the disaggregation of mortars is, however, absent from the teristics of the mortar and tesserae, and thereby render the published literature apart from a few exceptions. Movement of mosaic more susceptible to deterioration by other factors, for water throughout a site (hydrology) has been investigated only example, water-related mechanisms. In addition, through eco- in a few cases, including a long-term project for the monitor- logical succession, algae or lichen can provide nutrition, mois- ing of the moisture content of the mosaics and surround- ture, and humus buildup for moss colonization, which in turn ing environment at Chedworth, United Kingdom (Stewart, paves the way for higher plant colonization (Garcia-Rowe, Berry, and Staniforth 2003). Th e importance of the relation- Saiz-Jimenez, and Sameño 1989; Puertas et al. 1994; Saiz- ship between a mosaic and its subterranean environment once Jimenez, Garcia-Rowe, and Rodriguez-Hidalgo 1991; Altieri, a mosaic is exposed through excavation has been explored in Poggi, and Ricci 2003: 256). Physical disruption of pavements Switzerland at Orbe-Boscéaz (Weidmann et al. 2003: 173–74), by roots, from weeds to trees, is reported by several authors as where hydrological studies have been carried out to investigate one of the principal causes of deterioration on in situ mosaics the eff ect of groundwater and of soluble salts. At this site, test- (Villa 1978; Veloccia 1978; Bassier 1978; Chantriaux-Vicard ing on simulated mosaic samples and direct measurements 1990) and is mentioned oft en in treatment case studies. on the mosaics identify temperature fl uctuations as the prin- Penetration of roots into the tessellatum may lead to cipal cause of the dilations and contractions and subsequent detachment and loss of individual tesserae (Aoyagi and Foschi deterioration observed on the mosaic (Flatt, Girardet, and 1997: 819) or loss of whole areas of the tessellatum and deterio- Weidmann 1997; Weidmann et al. 2003). ration of the bedding layer (Foschi 2000: 722). More signifi - Th e diagnostic research at the sites of Orbe-Boscéaz cant structural damage caused by roots of shrubs penetrating and Vallon in Switzerland and at Chedworth in the United below the bedding layer and causing bulging and subsequent Kingdom are among the best and most complete examples detachment of tesserae is also found (Gambogi, Fontanelli, of integrated scientifi c research and are reported in groups and Tuccino 1998: 155). Mechanical root damage leaves the of articles published over a period of several years on the mosaic open to further deterioration through the creation various steps of the investigations (Weidmann et al. 2003; of voids and the disruption of the cohesion of mortar layers, Guex 2003; Stewart, Julien, and Staniforth 2004). Promising including structural weakness when roots subsequently decay, and worth mentioning is the recently begun interdisciplinary and soil accumulation in cracks and voids, which leads to fur- research and conservation work at the important site of Piazza ther plant invasion (Roby 2003: 212). Armerina (Cosentino et al. 2004; Lazzarini et al. 2004; Palla and Anello 2004; Santalucia 2004). Human Action Th ermal fl uctuations around freezing point associated Human factors aff ecting the preservation of mosaics in situ with presence of water are an important cause of deteriora- can be seen as having the greatest signifi cance in relation to tion. Considerable damage can occur aft er only a few days of the current condition of a mosaic, as they principally con- freeze–thaw cycling when water is present in the porous com- cern human mismanagement of the mosaic, and are hence an TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) ponents and in the layered structure of a mosaic (Mingarro avoidable form of deterioration. Human impact on mosaic Martín 1989: 29) and in terracotta tesserae of opus signinum preservation includes deterioration related to both the lack of fl oors (Roncuzzi Fiorentini et al. 1985: 345). However, specifi c preventive actions to avoid or mitigate environmental causes references to this type of deterioration were surprisingly few of deterioration4 and the introduction of inappropriate treat- (see Bassier 1978: 69; Chantriaux-Vicard 1990: 296; Fernandez ment materials and methods. 1987: 284; Weidmann et al. 2003: 170). The increase of mass tourism is a danger for all sites, and Th e irregular surfaces of most excavated mosaics are its regulation should fall under site management (Melucco particularly suited to microbiological colonization as they Vaccaro 2003: 19). Experience shows that people walking provide for localized buildup of moisture and soil and nutri- on mosaics can cause accidental damage by dislodging or tive mineral sources. A general overview of biodeterioration abrading/eroding the tesserae, especially the softer and more of mosaics has been published (Monte Sila 1989). A large body porous ceramic, clay-based, and glass tesserae, but there is of scientifi c literature concerning biological causes of deterio- little documentation of this well-known process. An addi- ration comes from fi eldwork carried out at the site of Italica tional consequence of tourism is the use of water by tourist in Spain. Th ese studies have shown that microorganisms can guides and tourists themselves to saturate the colors of mosa-

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Learning from the Literature 37

ics and increase their legibility (Costanzi Cobau and Nardi and repeated expressions of the destructive aspects of detach- 2003: 331), with negative impact on the mosaics through the ment, in situ conservation is today much more common. increase in wetting and drying cycles. Over the past twenty years, there have been few articles Perhaps the most insidious cause of deterioration is synthesizing current practice; instead, they have focused neglect. Th ere are numerous examples of the abandonment of instead on the “bigger picture,” addressing what is seen as mosaics immediately aft er their excavation, or even aft er exten- an overriding priority: developing management strategies sive conservation treatments. Th e lack of regular maintenance, for archaeological sites, most notably, to address inadequate although infrequently discussed in the published literature until planning and the lack of resources for maintenance (Melucco two decades ago,5 has gradually become a concern and is now Vaccaro 2003; Nardi 1994b). A schematic diagram, which both recognized as a major contributor to the rate and extent of highlights the importance of following a decision-making pro- deterioration and loss of excavated mosaics. Th e 1996, 1999, cess and emphasizes that management decisions have to be and 2002 ICCM conferences include references to maintenance made in the wider site and regional context of a mosaic, pre- programs now being carried out at individual sites (Nardi 2003; sented at the 6th ICCM conference in 1996, illustrates this shift Margalit 2003; see also Zizola 2005), as well as initiatives for the in perspective from the micro to the macro level (de Guichen on-site testing of maintenance methods (Piqué, Neguer, and 2003: 14; see also Nardi and de Guichen, this volume). Lucherini 2003) and the on-site training of maintenance techni- Treatment methods and materials historically have not cians (Roby, Alberti, and Ben Abed 2005). Th e need for “a plan been reported on in any detail in the literature, and a review of of long-term maintenance” was included as one of the recom- published case studies shows that this has changed only in the mendations of the 1999 conference (ICCM 2001, 2003). past ten years or so. Th is period also sees overall an increas- Another human factor reported as a cause of deteriora- ingly uniform approach to the in situ treatment of mosaics. tion is past interventions. While the use of inappropriate mate- Methods for intervention seem to be restricted largely to mor- rials in the past, notably, reinforced cement supports (Bassier tar repairs, grouting, and cleaning, with very few references 1978: 70) and cement mortar repairs (Gambogi, Fontanelli, and to interventions more common in the related fi elds of wall Tuccino 1998: 154; Tripodi 1997: 238, 240), is represented in the painting and stone conservation (e.g., surface protection, con- literature, published observations of the detrimental results solidation, and desalination). of such practices are in fact few in number. Th e use of acids Th e majority of treatment detail found in the literature for cleaning is known to have been a common practice, but describes the use of lime-based materials for mosaic stabi- only very occasional reference to their use is found (Menicou, lization, indicating widespread use of slaked and hydraulic Fiori, and Macchiarola 2003: 229; Pastorello and Schmid 1991: limes. Th ese materials are used for a variety of stabilization 59–60; Chantriaux-Vicard 1990: 286). operations, including infi lling of lacunae and tesserae interstices, resetting of detached tesserae, and injection grouting (e.g., Roby 1994; Aoyagi and Foschi 1997; Demitry 1994; Nardi Treatment Interventions as Discussed in the 2004). Th e publication of ICCROM’s testing of a grout for Published Literature stabilizing mosaics in the 1980s (Ferragni et al. 1985) not only Treatment is any “direct” intervention on the materials of the helped to turn the tide toward in situ conservation by provid- mosaic to clean, stabililize, and improve its aesthetic appear- ing the technical means to do so as an alternative to detaching ance; as such, treatment here does not cover the wider preven- them, but was also the precursor to case studies reporting tive measures of preservation in situ, such as sheltering and the use of injection grouting (Demitry 1994: 166; Roby 1994; reburial. Albini, Costanzi Cobau, and Zizola 1996: 4). At the time of the fi rst ICCM meeting in 1977, the com- Th e use of synthetic materials for stabilization treatments mon response to the need to preserve pavement mosaics was is only occasionally mentioned and is limited to the reattach- their detachment followed by transfer to a museum or re-laying ment of tesserae and occasionally as an additive for grouting them on new foundations (see, e.g., Bassier 1978; Veloccia (Roby 1994: 35; Ferragni et al. 1985: 93). Experimentation with 1978). At that meeting, however, discussions about in situ con- synthetic organic materials seems to have been in general brief servation were already under way, and a trend away from (see, e.g., Bassier 1988). Recently, the fi rst handbook devoted detachment can be seen in the literature from then onward. to mosaic conservation was published; it includes a compre- Facilitated by improvements in in situ treatment techniques hensive list of materials potentially suitable for use in mosaic TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 37 TJ14-3 P007-066 200L CTP.indd 37 3/3/08 11:22:32 AM Black

38 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

conservation and a brief description of the processes of docu- signifi cant changes have taken place in the past three decades. mentation, preconsolidation, cleaning, repairs, stabilization, First, there has been a general increase in the number of arti- and protection (Fiori and Vandini 2002: 69–74); however, few cles dealing with mosaic conservation not only in terms of of these materials appear in the literature on in situ mosaics. treatment case studies, written for the most part by conserva- Materials that do occur infrequently in the literature tors and art historians, but also in terms of scientifi c research, include aqueous cleaning solutions (EDTA, ammonium car- protection interventions, and site management, written by bonate, the disinfectant/surfactant NeoDesogen (benzalco- managers, archaeologists, scientists, architects, and engineers. nium chloride) (e.g., Cenciaioli, Botti, and Scaleggi 1998: 179); Th is refl ects the increased interest and attention to this type adhesives and consolidants, including acrylic copolymers and of heritage and the emergence of a more multidisciplinary silicates (e.g., Di Stefano 1997: 11); and, very rarely, surface approach to mosaic conservation. hydrorepellants (e.g., Tripodi 1997: 242). Biological activity, Th e more striking trends in the fi eld as refl ected in the from microbiological growth up to plant roots, has over time literature over the past few decades can be summarized as been controlled by a variety of chemical methods. Of particu- follows: lar interest are two projects comparing the effi cacy of biocides during in situ testing (Monte and Roncuzzi Fiorentini 1989; 1. Publications on the conservation of mosaics in situ, Altieri, Poggi, and Ricci 2003) and laboratory testing of the on their original bedding foundations, have become eff ect of diff erent biocides on tesserae of various stone types predominant over those discussing detachment and (Mambelli et al. 1989). treatment of detached mosaics. Th e presentation and reintegration of losses, or lacunae, 2. Treatment interventions in situ reported in the lit- in mosaics has been a subject of much debate over the years, erature over the past two decades are almost exclu- although confi ned largely to practitioners in Italy. Th e subject is sively limited to lime-based interventions (mortars responsible for a signifi cant proportion of the literature on mosaic and grouts) and localized use of synthetic polymer conservation, including the proceedings of a meeting dedicated adhesives, with little use of consolidants, surface to the subject in Italy in 2002 (Foschi, Lugari, and Lucagni 2003). protectants, or other materials found commonly in While the issue of compatibility of materials, and their possible the allied fi elds of stone and wall painting conserva- performance and durability over time, is occasionally mentioned tion. Th e use of cement is no longer reported in the (e.g., Laurenti 2003), most articles are concerned with aesthetic literature. and historical issues of presentation (e.g., Philippot 1978; Lugari 3. Th ere has been an increase in publications on sci- 1998; Foschi, Lugari, and Lucagni 2003). entifi c aspects linked to the study of deterioration, Testing programs to develop treatment interventions are refl ecting increasing awareness of the need for rarely discussed in the literature. In addition, very few articles diagnostic studies to address deterioration prob- that evaluate past treatment interventions have been published. lems. However, few studies that integrate analytic Th e performance over time of repair work and the impact of any studies with on-site management and treatment TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) treatments on the original mosaic materials are rarely evaluated interventions have been published. Exceptions, but of extreme importance. Mention should be made of the notably at Orbe-Boscéaz and Vallon in Switzerland, enormous potential of noninvasive tools for both diagnostic at Chedworth in the United Kingdom, and, most investigations and monitoring of condition and treatments over recently, at Piazza Armerina, are noteworthy for time (techniques adopted from the fi eld of geophysics such as multidisciplinary teamwork and long-term com- georadar, tomography, and thermography have been used to mitment to research and conservation (given the assess condition but, again, with no specifi c link to subsequent diffi culty and the scale of research required for treatment choices) (Iannucci et al. 1997; Schirripa Spagnolo, diagnostic investigation at sites, a good case study Ambrosini, and Paoletti 2003; Cosentino et al. 2004). requires extensive multidisciplinary research and can seldom be represented in a single article). 4. Th ere have been an increased number of articles Conclusion advocating more holistic, preventive approaches to Review of the large and heterogeneous body of literature on mosaic conservation, stressing the importance of mosaic deterioration and treatment has indicated that some planning and management of a site, and attempting

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Learning from the Literature 39

to move the emphasis away from single-site treat- Notes ment of mosaics to viewing the mosaic resource as a whole, on both the site and the regional scale. 1 Th e literature review in its entirety will be available online in the 5. “Lack of maintenance” has become predominant in near future. the published discussions on causes of deterioration, 2 Th e literature search intentionally focused on mosaics, thus especially over the past ten years, and examples of excluding the literature on stone and wall paintings conservation research and training initiatives to support regular that would be relevant to mosaic conservation. Th is choice was made in order to understand the state of in situ mosaic maintenance cycles have recently appeared in the conservation. Also, while the project bibliographic database published literature—although few examples of pro- includes a large number of publications concerning the lift ing and grams of maintenance have as yet been reported on. re-laying of mosaics and the treatment of detached mosaics, these 6. Th e evaluation of the effi cacy of treatment interventions were not included in the literature review given its focus on in situ over time is noticeably lacking in the published litera- conservation of fl oor mosaics. For the same reason, the literature ture, and studies for the selection of suitable materials on wall mosaic conservation has generally been excluded, with the exception of illustrative articles focusing on analysis of constituent and methods for treatment are extremely rare. materials and deterioration of excavated fragments.

In many aspects, mosaic conservation as seen through 3 Over two hundred references to one or more of the categories of deterioration, treatment, and maintenance were reviewed in detail the literature is following the trends of immovable heritage for these parts of the literature review. conservation and slowly shift ing toward better site management and planned conservation maintenance. It is hoped that 4 Sheltering and reburial of mosaics are dealt with separately in other sections of the literature review; recent publications that this will include more widespread training of conservation and discuss these interventions are Aslan 2003; Solar 2003; Stewart, maintenance professionals and the development and applica- Berry, and Staniforth 2003 (shelters); Roby 2003; Stewart 2004: tion of objective scientifi c techniques to support diagnostic 240; Neguer 2004 (reburial).

studies and to monitor mosaic conditions over time. 5 Only 2 out of 400 titles reviewed by Nardi (up to and including 1988) mentioned lack of maintenance as a cause of deterioration Acknowledgments (Nardi 1994a: 345). Th e authors would like to express their gratitude to those who have been involved over the years in the mosaic conservation References literature review project or have provided valuable comments Abd El-Hady, M. M. 1990. Deterioration of mosaics in the Mamluk on draft s of the full review text summarized in this paper. buildings in Cairo, Egypt. In Mosaicos, no. 5: Conservación in situ, Th ese include both current and former Getty Conservation Palencia, 1990: IV Conferencia general del Comité Internacional Institute colleagues: Neville Agnew, Elsa Bourguignon, Evin de Mosaicos, ed. ICCM and ICCROM, 27–36. Palencia: Excma. Erder, Eric Hansen, Bettina Lucherini, Gaetano Palumbo, and Diputación Provincial, Departamento de Cultura. Sibylla Tringham, as well as Jerry Podany of the J. Paul Getty Al-Azm, A. 2004. Conservation and preservation of mosaics in Syria: Museum. External reviewers Livia Alberti, Giorgio Torraca, Examining the case to remove or restore in situ from a Syrian and Denis Weidmann have also contributed their considerable perspective. In Apparati Musivi Antichi nell’area del Mediterraneo, Atti del I Convegno internazionale di studi, la materia e i segni experience and expertise to revising earlier versions of the lit- della storia, Piazza Armerina, 9–13 aprile 2003, ed. G. Meli, 198– erature review. Bibliographic searches and retrieval were pro- 200. I Quaderni Di Palazzo Montalbo, 4. Palermo: D. Flaccovio vided by GCI Information Center staff Valerie Greathouse and Editrice. Tom Shreves. We would also like to thank Benjamin Marcus, Albini, R., A. Costanzi Cobau, and C. Zizola. 1996. Mamshit, 2006–7 graduate intern at the Getty Conservation Institute, Israel, and San Paolino alla Regola, Rome: What cooperation or for his research assistance in connection with the draft ing and interference between archaeologist and conservator can achieve. revision of this paper. In Archaeological Conservation and Its Consequences: Preprints of the Contributions to the Copenhagen Congress, 26–30 August 1996, ed. A. Roy and P. Smith, 1–5. London: International Institute for Conservation of Historic and Artistic Works. TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 39 TJ14-3 P007-066 200L CTP.indd 39 3/3/08 11:22:32 AM Black

40 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

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Orbe-Boscéaz (Canton de Vaud, Suisse) 1975–2005 : 30 ans de réflexions sur la conservation d’anciennes et de nouvelles mosaïques

Denis Weidmann

Résumé : Les mosaïques d’une villa romaine au nord des Des travaux d’entretien et de conservation ont été eff ec- Alpes ont été découvertes, maintenues in situ sur leur support tués à diverses reprises sur les mosaïques in situ au cours du d’origine et mises sous abri dès 1841. Des menaces sur le site et 19e et du 20e siècle, avec des méthodes et matériaux en usage la dégradation des mosaïques ont nécessité des interventions dans les périodes correspondantes. Leur bilan fait apparaître dès 1975. Les conditions de conservation et les altérations sont que les interventions du 19e siècle – réalisées par des artisans étudiées méthodiquement depuis 1993. Le résultat des études des métiers traditionnels de la maçonnerie et de la pierre – défi nit les programmes individuels d’intervention sur les pave- conservent une remarquable compatibilité avec les matériaux ments, ainsi que les modifi cations apportées aux abris. et structures antiques. En revanche, les travaux de la première moitié du 20e siècle ont entraîné une partie des problèmes Abstract: Th e mosaics from a Roman villa in the northern Alps d’altération observés. were discovered, maintained in situ on their original support, and sheltered in 1841. In 1975, threats to the site and the degradation of La conservation du site the mosaics made interventions necessary. Th e conditions under which the mosaics are conserved and the alterations they have A partir des années 70, le projet d’un tracé d’autoroute aff ectant suff ered have been methodically studied since 1993. Th e results of la région des mosaïques a fait reconsidérer la situation locale. the studies determine the individual intervention programs on the La nature du site et son extension étaient encore indétermi- pavements, as well as the modifi cations made to the shelters. nées, l’exploration archéologique du périmètre n’ayant jamais été entreprise. Des photographies aériennes réalisées à la faveur TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) Les neuf mosaïques de la villa gallo-romaine d’Orbe consti- de la sécheresse de l’été 1976 ont livré très opportunément tuent un ensemble caractéristique des situations de conserva- le plan complet du site, d’une superfi cie de 16 hectares, ainsi tion in situ au nord des Alpes (Von Gonzenbach 1961: 173–199). que la disposition générale de l’immense résidence à laquelle Découvertes dès le milieu du 19e siècle, la plupart ont aussitôt appartiennent les diverses mosaïques (Flutsch, May Castella fait l’objet de mesures de protection et de conservation qui et Paratte 1997). Le constat de l’existence d’un site de grande apparaissent aujourd’hui comme très en avance sur leur temps ampleur, préservé dans le terrain et doté de plusieurs mosaï- (Weidmann 1987). Pour garantir la préservation d’un patri- ques de haute valeur, encore in situ, a suscité une politique moine important dans un paysage rural, il a été décidé en 1841 générale de conservation de la villa, avec la perspective d’une et 1862 de déplacer le tracé d’une route et de construire deux mise en valeur. Le premier eff et de cette orientation a consisté bâtiments de protection en maçonnerie pour soustraire les en un choix de tracé routier ménageant le site, et permettant à mosaïques aux infl uences climatiques, assurer leur sécurité et la même occasion de supprimer la route qui l’oblitérait encore. permettre leur présentation (fi g. 1). Les mêmes interventions Ces travaux ont été associés à un programme d’exploration de de protection ont été répétées à deux reprises sur le site au 20e la pars urbana de la villa (environ 250 × 80 m), conduit par siècle, mais avec une moindre qualité et effi cacité. l’Université de Lausanne. Le site, entièrement arasé et conservé

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Orbe-Boscéaz 1975–2005 : 30 ans de réflexions 47

FIGURE 1 Projet du premier bâtiment de protection des mosaïques réalisé en 1841 par l’ingénieur des Ponts et Chaussées du Canton de Vaud.

sous une très faible épaisseur de terrain labouré, a été fouillé Notre inexpérience en ce domaine nous a amenés à sol- en 19 étapes annuelles, de 1986 à 2004. L’état de conservation liciter des expertises extérieures, dont celle de Claude Bassier, des vestiges exposés aux activités agricoles a été contrôlé et il de Périgueux, en 1978. a été procédé au réenfouissement méthodique des structures Il a aussitôt identifi é les principaux facteurs de dégra- dégagées. La protection du site a été résolue en faisant acquérir dation, liés à l’évaporation et à la concentration des sels. La l’emprise de la villa par l’État et en proscrivant dorénavant le solution préconisée a été de procéder à une dépose générale et labourage et la culture du terrain. à un transfert sur panneaux, assurant à la fois la sécurité des Pour les mosaïques, en plus de la protection générale, pavements et leur indépendance des conditions du sous-sol. les acquis directs sont la découverte d’un nouveau pavement (Achille à Skyros), la connaissance de leur contexte archéolo- gique et architectural, ainsi que leur datation (fi g. 2).

La conservation des mosaïques On a vu que les questions de conservation ont constamment préoccupé les responsables. Des décollements et cloquages sont régulièrement apparus une vingtaine d’années après la mise au jour de chaque mosaïque, appelant des interventions ponctuelles. La reprise en main du site, dans les années 1970, a été associée à un nouvel examen de l’état des pavements, qui présentaient tous des signes inquiétants de dégradation. Avant toute intervention, il a été procédé à un inventaire des connaissances et documents relatifs au site, et en particulier aux interventions et restaurations antérieures. Les insuffi - sances documentaires et l’imprécision des descriptions font FIGURE 2 Plan d’interprétation de la pars urbana de la villa qu’il a rarement été possible d’identifi er les emplacements des après les fouilles méthodiques. En foncé : pièces à mosaïques travaux et leur justifi cation. conservées. Longueur du bâtiment : 250 m. TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 47 TJ14-3 P007-066 200L CTP.indd 47 3/3/08 11:22:36 AAMM Cyan Magenta Yellow Black

48 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

La proposition n’a pas été suivie, en raison de son coût explicatif des phénomènes qui ont conduit à l’état des dif- élevé et du changement considérable de l’aspect des mosaï- férents pavements et à une description des évolutions en ques qui en aurait résulté si elles avaient été mises à plat sur cours. Des indications précises ont ainsi pu être données des supports modernes. Les pavements in situ présentent en pour éviter les conditions critiques amenant les altérations eff et des tassements et irrégularités qui témoignent de leur constatées. longue histoire et de leur authenticité. Ces résultats ont bien entendu conduit aux diff érentes Simultanément, la prise de connaissance générale du décisions d’interventions, dont le programme se poursuit site environnant et de sa qualité donnait beaucoup plus de depuis plusieurs années. Les mesures générales qui ont été cohérence à la recherche d’un maintien général des éléments prises concernent avant tout le drainage du site et des abris, dans leur contexte. Nous avons ainsi suivi les résolutions de la la stabilisation climatique et la limitation des taux d’évapora- 4e conférence ICCM de Soria (1986). tion dans les mosaïques. Deux installations expérimentales de gestion des fl ux d’humidité atmosphérique fonctionnent dans les deux anciens Études, analyses et décisions abris, stabilisant l’état de deux importantes mosaïques. Les méthodes de traitement pour une conservation durable Les nouvelles conditions sont suivies par des mesures de dans la situation spécifi que d’Orbe n’étant pas établies d’em- contrôle et par des analyses, pour vérifi er les eff ets souhaités. blée, nous avons engagé une analyse générale de la situation et Un processus de séchage lent est en cours depuis plu- de l’état des mosaïques, pour comprendre les causes des alté- sieurs années pour la mosaïque nouvellement découverte, rations constatées. La découverte d’une nouvelle mosaïque en pour permettre sa consolidation en place et sa présentation. 1993, qui n’avait pas subi l’évolution historique de ses voisi- Un abri répondant aux conditions de conservation adéquates nes longuement exposées, incitait à défi nir des conditions de est à défi nir et à réaliser pour cet objet. Les mesures particu- conservation non dommageables et durables. lières de conservation et d’intervention ont pris la forme soit De nombreuses études et expérimentations ont été de dépose et de transfert sur de nouveaux supports, pour les conduites, sur plusieurs cycles annuels (Weidmann et al. trois mosaïques ou fragments qui avaient dépassé les seuils 2003). Elles ont conduit à une définition de certains para- critiques (taux de salinité, altération des matériaux, décolle- mètres limites pour la conservation visible (Flatt, Girardet ments généralisés), soit de conservation in situ, sur support et Weidmann 1997) ainsi qu’à des décisions d’intervention d’origine (fi g. 5). À ce jour, la situation de six des mosaïques et de traitements, selon l’évolution individuelle de cha- du site est rétablie et permet leur présentation au public. que mosaïque et les conditions que peuvent offrir les abris (Fischbacher et al. 2003 ; Flatt et Girardet 2000 ; Weidmann et Girardet 2005). Un premier groupe d’études a eu pour objet l’évolution des cycles climatiques, sur plusieurs années, sur le site, dans TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) l’ambiance des abris et dans une des mosaïques sujette à d’importantes déformations (fi g. 3). La corrélation des mou- vements du pavement et des variations climatiques a montré la nécessité de stabiliser les conditions dans les pavillons, par des travaux d’isolation et par la suppression de l’insolation directe sur les pavements. Simultanément, les caractéristiques des matériaux et des mosaïques (calcaires et mortiers) ont été analysées, pour apprécier l’importance des variations de l’humidité et de la température pour leur dilatation ou contraction. L’étude des teneurs en sels et en eau, à diverses profondeurs dans les sols et dans les mosaïques, ainsi que l’hy-

drogéologie du site, ont mis en évidence les différents états FIGURE 3 Enregistrement des déformations d’une mosaïque et physico-chimiques actuels (fig. 4). Il en a résulté un modèle des variations climatiques en 1993.

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Orbe-Boscéaz 1975–2005 : 30 ans de réflexions 49

FIGURE 4 Tableau général des analyses des teneurs en eau et en sels 9 93568 – – – – + solubles (SO4 , NO3 , Cl , K , 1996 2004 Na+) pour les mosaïques n° 3, 5, 6,

8 et 9 et pour diverses profondeurs. H2 O Sels H2 O Sels H2 O Sels H2 O Sels H2 O Sels H2 O cm %p.p. Mg/g %p.p. Mg/g %p.p. Mg/g %p.p. Mg/g %p.p. Mg/g %p.p. Les mosaïques 3, 5 et 6 ont été 0 0100010 10 00 10 10 0010 10 000010 10 10 10 0 déposées. T .50 N .50 3 .59 5 2.50 R .43 .49 10 S .65 .46 20 .75 .60 30 .56 40 .62 50 .59 60 .35 1.03 H O 141.5 2 mg/l

FIGURE 5 Après consolidation par injections, nettoyage des surfaces par micro-sablage pour éliminer les restes des anciens traitements. TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 49 TJ14-3 P007-066 200L CTP.indd 49 3/3/08 11:22:43 AAMM Black

50 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

En conclusion de cette expérience d’intervention conti- Flatt, R. J., F. J. Girardet et D. Weidmann. 1997. In situ nue sur trois décennies, nous dégageons le bilan suivant : conservation of the Roman mosaics at the Villa of Boscéaz (Orbe, Switzerland): Diagnosis of risks involved. Dans Materials Issues in Art and Archaeology V : Symposium Held • Le traitement des mosaïques est indissociable de December 3–5, 1996, Boston, Massachusetts, USA, ed. J. F. celui du site dans son ensemble ; Merkel and J. Stewart, 317–22. Materials Research Society • Seule une analyse approfondie de la situation et de Symposium Proceedings, vol. 462. Warrendale, Pa. : Materials l’état des objets peut orienter les mesures à prendre ; Research Society. • La complexité des phénomènes qui aff ectent les Flutsch, L., C. May Castella et C.-A. Paratte. 1997. La villa objets à conserver in situ impose de considérer les cas gallo-romaine d’Orbe-Boscéaz et ses mosaïques. Guides individuellement ; Archéologiques de la Suisse, ed. Fondation Pro Urba et la • La lenteur des processus dans le terrain impose un Société suisse de préhistoire et d’archéologie, no. 5. Orbe : Fondation Pro Urba. suivi et des contrôles à long terme. Gonzenbach, V. von. 1961. Die Römischen Mosaïken der Schweiz. Nos partenaires et mandataires pour ce projet sont les Monographien zur Ur- und Frühgeschichte der Schweiz, vol. 13. Basel : Birkhäuser. responsables et collaborateurs des institutions suivantes : Weidmann, D. 1987. Problèmes de gestion et de conservation des • Expert-Center pour la conservation du patrimoine mosaïques d’Orbe-Boscéaz (Vaud-Suisse), abritées depuis 1841. Dans Mosaicos, no. 4 : Conservación « in situ », Soria bâti, Lausanne et Zurich ; 1986 = Mosaïque, no. 4 = Mosaics, No. 4 : Proceedings of the • Laboratoire de géologie de l’École polytechnique 3rd General Conference of the International Committee for the fédérale de Lausanne (EPFL) ; Conservation of Mosaics, ed. ICCM, 7–17. Soria, Spain : Servicio • ABA Geol - Payerne ; de Investigaciones Arqueológicas, Disputación Provincial de • Weinmann - Énergies - Echallens ; Soria ; Instituto de Conservación y Restauración de Bienes • Laboratoire du Musée Romain - Avenches. Culturales, Ministerio de Cultura. Weidmann, D., R. Flatt, C. Félix, F. Girardet et A. Glauser. 2003. Analyse des altérations et déformations de mosaïques à Orbe- Références Boscéaz (Canton de Vaud, Suisse). Dans Mosaics Make a Site: Th e Conservation in Situ of Mosaics on Archaeological Fischbacher, V., R. Flatt, F. Girardet, M. Kaufmann et Sites: Proceedings of the VIth Conference of the International D. Weidmann. 2003. Traitement in situ de mosaïques à Committee for the Conservation of Mosaics, Nicosia, Cyprus, Orbe (VD - Suisse). Dans Les mosaïques: Conserver pour 1996, ed. D. Michaelides, 169–84. Rome: ICCM. présenter ? VIIème Conférence du Comité international pour Weidmann, D., et F. Girardet. 2005. Contrôle climatique de la conservation des mosaïques, 22–28 novembre 1999, Musée de mosaïques in situ sous abris. Dans 8o Synedrio Diethnous l’Arles antique, Arles, Musée archéologique de Saint-Romain-en- Epitropes gia te Synterese ton Psephidoton (ICCM) : Entoichia Gal : Actes = Mosaics, Conserve to Display ? VIIth Conference of kai epidapedia psephidota : Synterese, diaterese, parousiase : the International Committee for the Conservation of Mosaics : TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) Th essalonike, 29 Oktovriou–3 Noemvriou : Praktika = VIIIth Proceedings, ed. P. Blanc, 155–61. Arles : Musée de l’Arles et de la Conference of the International Committee for the Conservation Provence antiques. of Mosaics (ICCM) : Wall and Floor Mosaics : Conservation, Flatt, R. J., et F. J. Girardet. 2000. Injectable slurries for the in situ Maintenance, Presentation : Th essaloniki, 29 October–3 conservation of pavement mosaics. Dans Proceedings of the 9th November 2002 : Proceedings, ed. Ch. Bakirtzis. Th essalonique: International Congress on Deterioration and Conservation of European Center of Byzantine and Post-Byzantine Monuments. Stone, Venice, June 19–24, 2000, ed. V. Fassina, vol. 2 : 297–305. New York : Elsevier.

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Villa of the Birds Five Years Later: Early Roman Mosaics in Alexandria, Egypt

Jarosław Dobrowolski

Abstract: In 1998–99 the mosaic fl oors of an early Roman villa in under excavation by the Polish Center of Mediterranean Alexandria, Egypt, were conserved in situ. Th is was a project of Archaeology since 1960, is so important: it is the only frag- the American Research Center in Egypt, fi nanced by USAID and ment of the ancient city that can be seen today. The site cov- carried out in cooperation with the Egyptian Supreme Council ers about 40,000 square meters (4 ha) in the center of both of Antiquities and the Polish Center of Archaeology in Cairo. modern and ancient Alexandria. From the fourth or fifth Th is paper addresses the position of the mosaics as a part of the century c.e. onward, it housed public buildings, including larger archaeological site fi ve years aft er their conservation was a huge bath complex complete with gymnasia and service completed. Included are a review of the mosaics’ display, the facilities and a series of academic auditoriums, the biggest of design principles of the protective shelter compared to the actual which is the “Roman Theater.” The site also includes part of visitation patterns, the maintainance needs for the mosaics and a district composed of modest residential houses and work- the shelter, and the condition of the mosaics aft er fi ve years. shops. Below these monuments lies a district of rich urban villas dating from the first to the third century c.e. These Résumé : En 1998–1999, des pavements en mosaïques appar- buildings were destroyed in antiquity and their rich mosaic tenant à une villa romaine à Alexandrie, en Égypte ont été floors buried under rubble, which preserved them. conservés in situ. Ce projet de l’American Research Center en In 1998–99 the American Research Center in Egypt Égypte a été fi nancé par l’USAID et mis en œuvre avec le Conseil conserved and displayed in situ a set of mosaic fl oors from Suprême des Antiquités d’Égypte et le Centre archéologique one villa. Th e project was fi nanced by the U.S. Agency for polonais du Caire. Cette communication aborde les mosaïques International Development (USAID) and carried out by a dans le contexte plus large du site archéologique cinq ans après team from the Polish Center of Archaeology in Cairo in coop- leur traitement de conservation, ainsi que la mise en valeur des eration with the Egyptian Supreme Council of Antiquities mosaïques, la conception de l’abri par rapport à la fréquenta- (SCA). Th e technical aspects of the conservation were pre- tion actuelle, les besoins d’entretien des mosaïques et de l’abri sented by Ewa Parandowska, the project’s chief conservator, et l’état des mosaïques cinq ans plus tard. at ICCM’s seventh conference, in Arles in 2000 (Parandowska 2003). More than fi ve years aft er completion of the project, the For many centuries after its founding by Alexander the Great displayed mosaics have become a fi xture within the broader in 332 b.c.e., Alexandria, then the capital of Egypt, was one landscape of the site. of the world’s finest and most important cities. In the Middle Th e mosaics were fi rst discovered in the 1970s in trenches Ages, however, it was reduced to the status of a small and excavated in the area of late Roman (Byzantine) buildings insignificant harbor town. When the city regained its impor- and reburied (fi g. 1). Th e fi rst important decision to be made tance in the nineteenth and twentieth centuries ancient before the work started in 1998 was choosing which mosaics to Alexandria was buried deep beneath the expanding mod- display. Th e decision to present a set of mosaics belonging to a ern town. It is for this reason that the site of Kom al-Dikka, single house determined the extent of the reexcavation as well

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52 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

FIGURE 1 Th e site in 1997, before the inception of the mosaics conservation project. Photo: Robert (Chip) Vincent.

as the location and size of the protective shelter to be built. It was not possible to excavate the entire house, as more than half of it lies buried under a tall escarpment, on top of which stands Alexandria’s main Fire Brigade compound. Th e area ultimately excavated and included within the shelter measures FIGURE 2 A sketch plan of the original extent of the house (in 15 by 12 meters and covers less than one-third of the original blue) and the shelter over the excavated mosaics (in red). Sketch: Jarosław Dobrowolski, based on a plan by Wojciech Kołątaj. building, the extent of which can be determined from the grid of regular streets and building lots identifi ed during the excavations (fi g. 2). Because of the subject matter of a spectacular mosaic fl oor in it, the house was named Villa of the Birds (fi g. 3). Other fl oors included animal, fl oral, and geometric decorations in mosaic, as well as a partially preserved opus sectile fl oor in the house’s onetime triclinium. Ruins of late TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) Roman houses, restored in the 1980s, stood over the remnants of the villa. Th ese houses were built about one hundred years aft er the villas were abandoned and follow a diff erent street grid. Th eir foundations stopped just short of reaching the earlier fl oors, which made the survival of the mosaics possible. Th e design of the shelter over the mosaics, which are presented in situ, is a crucial element of the presentation. Th e architect, Wojciech Kołątaj, a conservation architect who was also the project director and had overseen restoration work on the site for many years, decided to incorporate the late Roman structures into the shelter by using some of them as its walls. Although some structures located directly above the mosaics FIGURE 3 Mosaic fl oor panel with purple gallinule (Porphyrio had to be removed, this design permitted the preservation of porphyrio). Th e Egyptian subspecies is depicted. Photo: Robert many of the later walls, thus retaining their relationship to the (Chip) Vincent.

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Villa of the Birds Five Years Later 53

FIGURE 4 Th e shelter over the Villa of the Birds. Photo: Jarosław Dobrowolski.

earlier villa. It also allowed for the sizable structure of the shel- servation team, and the American Research Center, as well ter to be less obtrusive in the landscape of the site (fi g. 4). as USAID, the funding body. Various aspects of the overall An important consideration was to make the shelter a design were discussed and refi ned in numerous on-site meet- single undivided space without internal columns. Th is was ings, usually requested by the architect. Th is concerned a mul- important for the presentation of the mosaics, as well as for the titude of questions, for example, the exact size and position aesthetic appeal of the interior. Building a roof over a span of of the shelter, the advantages of a single-space interior versus 12 meters requires the use of girders or similar structural ele- the increased diffi culty of constructing it, and even the color ments, which in most circumstances is not a big engineering of the roof cover. In the latter case, the options discussed were challenge. In this case, however, because it was not possible a roof that would be reminiscent of ancient roof tiles or one to bring heavy equipment to the site, innovative thinking was that would be neutral and unimposing in the landscape while required to build the roof over the fragile mosaics, which, clearly recognizable as a modern structure. Th e latter option adding to the diffi culty at hand, were simultaneously under was chosen. conservation. Th e girders were welded from smaller pieces on Conservation always includes an element of surprise a platform built at the level of the roof and then rolled one by that requires fl exibility on the part of the conservation team. one into their positions over steel beams that served as rails In this case, a previously unknown mosaic of superb qual- for this operation, later being used as supports for the fi nished ity was discovered outside the limit of the designed shelter roof. Th e grade outside the shelter corresponds to the late (fi g. 7). To include it in the display, an extension to the shelter Roman level, and it is from this level, about 1.50 meters above was built, its reinforced concrete walls forming a cave under the mosaic fl oors, that visitors see the mosaics from viewing the tall escarpment behind the shelter. Safety considerations galleries constructed of steel beams. Th is, in addition to the determined how much of the mosaic could be displayed. walls made of huge glass panels that are discreetly framed and Protecting the mosaics from dampness was a major the lightweight structure of the roof, has resulted in a light issue. Waterproof insulation protected the shelter from water and spacious interior that does not overwhelm the displayed coming down the escarpment. However, though a rainwater mosaics (fi gs. 5, 6). disposal system using the ancient sewage channels was thor- Th e design and construction of the shelter was a con- oughly designed, moisture from the ground remained a prob- tinuous process of discussion among the architect, the con- lem. Th is was mitigated by an aeration system of perforated TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 53 TJ14-3 P007-066 200L CTP.indd 53 3/3/08 11:23:23 AM Cyan Magenta Yellow Black

54 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

FIGURE 5 Interior of the shelter. Photo: Robert (Chip) Vincent. FIGURE 6 Interior of the shelter. Photo: Robert (Chip) Vincent.

pipes buried in trenches fi lled with nonporous gravel that was the mosaics with perforated pipes of a bigger diameter, which installed around the excavated mosaics. Th is allows moisture greatly reduced the scale of the problem. However, soluble to evaporate from the ground through the pipes rather than salts, carried by water and left on the surface when water through the mosaics’ surface. evaporates, continue to form light effl orescence in some areas. With the conservation completed, an opening ceremony Periodically, the Polish team removes the salts mechanically, was held on January 21, 2000, and the mosaics display was opened to the public. Th e exact number of visitors to the Kom al-Dikka site is diffi cult to obtain, but according to the SCA’s on-site inspectors, more than ten thousand people visited in 2004, most of them foreigners. In peak season about three hundred people arrive per day. Only some sections of the huge Kom al-Dikka site can be visited at present, and the main attraction continues to be the Roman Th eater. Tickets for the Villa of the Birds are sold separately at the same counter that dispenses tickets for the Roman Th eater, but only a fraction of TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) the tourists—one thousand per year, or roughly 10 percent— include the villa in their itineraries. Th e SCA assigned fi ve inspectors to be responsible for both the mosaics display and the excavations carried out by the Polish team elsewhere on the site. Th is refl ects the fact that the maintenance of the mosaics is largely considered the responsibility of the Polish Center, and indeed the Polish team has continued to care for the mosaics aft er the USAID-funded project ended. Th e shelter performs well and requires only routine maintenance or small-scale improvements, such as those made to the water disposal spouts and introducing one more oper-

able window for better ventilation. Penetration of moisture FIGURE 7 Floor mosaic with an emblema of a panther. Th e from the ground remains a persistent problem, however. In ancient repair may refl ect an intentional change from a hunting 2004 the Polish Center replaced the aeration drainage around scene into a Dionysiac emblem. Photo: Robert (Chip) Vincent.

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Villa of the Birds Five Years Later 55

FIGURE 8 Eastern part of the Kom al-Dikka site aft er completion of the project in 2000, with the shelter over the Villa of the Birds mosaics. Photo: Robert (Chip) Vincent.

by gently brushing them away. Th e mosaics are then cleaned of issues related to the protection of cultural heritage among with ethyl alcohol to protect against fungi. Th e SCA takes people who live in proximity. care of the daily operation of the display, which requires only Another factor that might have contributed to reduc- minimum maintenance. It is worth noting that smoking is ing the abuse of the site was the change in its perceived status not permitted in the shelter, which is important in a country brought about by the landscaping of the area next to the Villa where cigarette smoking is an omnipresent custom. of the Birds. As part of a large-scale upgrading of the city In addition to the threats posed to the mosaics by natu- district, the governor of Alexandria stepped in and had grass ral factors such as rainwater and moisture in the ground com- planted on the slopes of the deep excavated pit in which the bined with the presence of soluble salts, the location of the ancient ruins stand. Th is change, prompted by the work on the site in the center of the modern city poses some problems. Villa of the Birds, radically transformed the appearance of the Th e Alexandria Fire Brigade, itself located in a fi ne historic site (fi g. 8). building (although younger by some eighteen hundred years In conclusion, the lessons learned from the experience than the Villa of the Birds), can be a troublesome neighbor. of conserving and displaying the Kom al-Dikka mosaics can Its barracks, bordering on the site, have in the past been the be summarized as follows: source of massive water leakage and of a considerable amount of garbage thrown onto the site. Huge amounts of water dis- • When mosaics are conserved and displayed in situ in charged by the fi refi ghters during their training drills also end a shelter, the shelter’s architectural design is vitally up on the site. Th ese problems have signifi cantly diminished important. It is not just an appendage to the conserva- in recent years, largely as a result of persistent explanations tion project but also a crucial element of the display. to the fi refi ghting authorities of the value and importance of It requires a highly skilled professional architect, pref- the site and the potential threats to it. Th is is an example of erably one with knowledge of the site and local condi- the crucial importance to preservation of raising awareness tions. Th e project must also allow for some fl exibility TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 55 TJ14-3 P007-066 200L CTP.indd 55 3/3/08 11:23:35 AAMM Black

56 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

in the implementation of both the conservation and Th ese conclusions are hardly surprising, since the conser- the design. Conservation work inevitably involves ele- vation of mosaics is not fundamentally diff erent from other ments of surprise and experiment, and this has to be forms of protection of cultural heritage. taken into account when structuring the project. • It is essential that the long-term preservation of the conserved mosaics be overseen by permanent cus- References todians who are both physically and institutionally Parandowska, E. 2003. Conservation of mosaics from the early present on-site. Conservation is a continuous process Roman villa at Kom al-Dikka, Alexandria. In Les mosaïques: rather than a onetime eff ort with defi nitive and per- Conserver pour présenter? VIIème Conférence du Comité manent results. international pour la conservation des mosaïques, 22–28 novembre • Conservation projects, in this case a display of mosa- 1999, Musée de l’Arles antique, Arles, Musée archéologique de = ics, are not isolated from their surroundings and their Saint-Romain-en-Gal: Actes Mosaics, Conserve to Display? VIIth Conference of the International Committee for the human environment. Th is can be an advantage, but it Conservation of Mosaics: Proceedings, ed. P. Blanc, 103–10. can also pose dangers. Arles: Musée de l’Arles et de la Provence antiques. • Finally, the fl ow of tourist traffi c is governed by its own rules, making it diffi cult to predict the number of visitors and patterns of visitation. TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S)

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Lessons Learned in Theory and Practice of Mosaic Treatments: The Case of the Wall Mosaics in the Church of the Holy Apostles, Thessaloniki, Greece

Charalambos Bakirtzis, Pelagia Mastora, Styliani Vassiliadou, and Nikos Pitsalidis

Abstract: Th is paper examines the theory and practice of small- 1984: 312–19; Demetriades 1985: 307–8; Nikonanos 1986: 10–12; scale, noninvasive, and mostly reversible interventions carried Kuniholm and Striker 1990: 1–25). Th e mosaics covered the out on the mosaic decoration in the Church of the Holy Apostles superstructure of the naos above cornice level, more or less in Th essaloniki. Th ese interventions involved strengthening the following the established iconographic program of Byzantine mosaics’ attachment to the masonry using Plexiglas anchor riv- churches (Xyngopoulos 1932: 133–56; Xyngopoulos 1953a; ets and solvent cleaning of the surface to remove grime and Nikonanos 1986: 34–55). Parts of the following mosaics sur- soot. In addition to improving the condition of the mosaics, the vive today: Christ Pantokrator and the prophets in the main results have enhanced the spiritual atmosphere of this Byzantine dome; the evangelists in the pendentives (fi g. 1); six dodeka- church. orton scenes in the barrel vaults (fi g. 2); the Dormition of the Virgin on the west wall; and saints, singly or in pairs, at the Résumé : Cette présentation traite de la théorie et de la pra- west end of the naos. Th e mosaics are characterized by the use tique des interventions à petite échelle, non invasives et pour of the style mignon, mainly in the fi gures in the dodekaorton la plupart réversibles, réalisées sur le revêtement en mosaïque scenes of the elegant, beautiful, expressive prophets, reminis- dans l’église des Saints Apôtres à Th essalonique. Ces inter- cent of ancient Greek sculptures, and in the vivid colors used ventions ont amélioré l’état des mosaïques en renforçant leur in the decorative vegetal motifs, which bring to mind models adhésion à la maçonnerie par moyen de rivets en Plexiglas et of Hellenistic and early Christian art. en procédant au nettoyage de la surface avec un solvant pour éliminer l’encrassement et la suie. Les résultats ont renforcé Previous Interventions l’atmosphère spirituelle de cette église byzantine. When the church was converted into a mosque in 1520–30, Th e mosaics in the Church of the Holy Apostles in Th essaloniki, the mosaics were concealed beneath a thick layer of plas- Greece, are among the few surviving mosaic ensembles of the ter (Demetriades 1985: 307–8). Th ey were uncovered gradu- Palaiologan era (1261–1453) and some of the last examples of ally during restoration work on the church conducted in that genre in Byzantium. Th e church, a cross-in-square ambu- 1926–28 (Xyngopoulos 1932: 133) and again in winter 1941–42 latory type, was the katholikon of a large Byzantine monastery (Xyngopoulos 1953a). Large areas of the mosaic surface were dedicated to the Virgin Mary that stood beside the west wall of found to have been destroyed by natural causes. It was also ascer- the city. Its founding and mosaic decoration are attributed to tained that almost all the gold tesserae had been removed from Niphon, patriarch of Constantinople (1310–14), though more the mosaic background before the mosaics were plastered over, recent views by Peter Kuniholm and Cecil Striker, based on as evidenced by their imprints, most of which were still pre- dendrochronology carried out on some of the church’s tim- served in the setting bed, which had survived in a few places. bers, bring the date forward to 1329 (Diehl, Tourneau, and Th e mosaics were restored in 1952 by the artist and Saladin 1918: 189–200; Xyngopoulos 1953b: 726–35; Rautman restorer Fotis Zachariou (Xyngopoulos 1953a). He fi lled in the

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58 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

FIGURE 1 General view of the dome and the pendentives aft er FIGURE 2 Th e west barrel vault aft er maintenance treatment. maintenance treatment. Photo by C. Bakirtzis. Photo by C. Bakirtzis.

areas of mosaic surface loss and covered the surviving mortar interventions. Th e aim was to detect, investigate, and interpret

TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) bed with a brownish red plaster; consolidated the detached any related problems so that it could be decided whether the mosaic surface with black cement, which he applied in the mosaics should undergo further conservation treatment and, interstices between the tesserae and in some areas around the if so, to what extent. mosaic surfaces as an “edging”; and cleaned the mosaic surface Th e main problems identifi ed during the examination and coated it with a specially made glossy varnish.1 of the mosaics fi ft y years aft er they had been restored were the following: (1) partial detachment of the mortar bedding layers from the masonry; (2) partial detachment of the later Current Investigations “neutral” plaster layer from the masonry and the mortar bed- Half a century later it was deemed necessary to examine the ding layers beneath it; (3) partial detachment of areas of the condition of the mosaics and improve their aesthetic appear- mosaic surface from the setting bed; (4) a network of hairline ance since they were covered by a thick layer of soot and cracks penetrating both the setting bed and the neutral plaster; grime. In fall 2002, with funding from the Th ird European (5) superfi cial cracks and a few deeper ones that, like the hair- Community Support Framework, the mosaics underwent line cracks, go through both the setting bed and the neutral preparatory cleaning. Th ey were closely examined and their plaster; (6) detachment of a large number of individual tes- condition described, as were the visible results of the 1952 serae; and (7) deposits of grime and soot both on the mosaic

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The Wall Mosaics in the Church of the Holy Apostles 59

established part of the mosaics’ aesthetic appearance. Indeed, in some places the grime soft ens their stark outlines and cre- ates convenient shadowy areas. Similarly, in other examples modern interventions have become an established part of a mosaic’s aesthetic appearance (Ardovino 2005: 63–72; Maguire and Terry 2005: 101–9). To remove the extensive brownish red areas and expose the masonry would create new com- peting surfaces that would detract from the presence of the fi nely craft ed mosaic representations. Given the chronologi- cal and economic planning of the project, together with the fact that the Holy Apostles is a functioning parish church, it was decided that the work done in 2004 would not go as far as a complete conservation treatment but would be limited to maintenance, with the principal aim of improving the mosaics’ stability on the masonry and removing the grime and other deposits from the mosaic surface over a period of ten years. FIGURE 3 Th e Resurrection before the removal of grime and other deposits. Photo by C. Bakirtzis. Mosaic Maintenance Program Improvement of the Mosaics’ Stability surface and on the neutral plaster (fi g. 3). Th ese are common Th e question of consolidating the mosaics on the masonry problems with wall mosaics but diffi cult to resolve in this case aroused considerable concern because the usual method of because of the irreversible procedures undertaken in 1952. in situ consolidation using grouting posed the dual risk of Th e 1952 interventions stabilized the mosaics, but the the neutral plaster either unifying with the mortar bed of the choice of cement (owing to its durability and color) as a mate- mosaics or solidifying on the masonry at those points where rial for conserving and presenting mosaics and the use of plas- the mortar bed had been totally destroyed. Although in the ter to fi ll in the areas of surface loss and cover the surviving current phase of the work the plaster would receive special parts of the mortar bed have created a situation that is techni- care and attention, it was decided to avoid “binding” it to the cally and aesthetically diffi cult to reverse, and one in which monument, based on the belief that as a foreign body it might both the original work and the previous treatments fall prey to one day be removed due to the risk that should the monument the same causes of deterioration. Furthermore, the interven- fall during an earthquake it would take the mosaics with it. tions have impaired the mosaics’ aesthetic appearance: they Additional reasons for not grouting with hydraulic mortar fi lled the interstices and concealed the shape of the tesserae were (1) the tesserae are very densely laid, especially in the in some places, obscured their colors with the dull gray of the dodekaorton scenes, which meant that the grout would have to cement, and marooned the mosaic representations in a sea of be injected only through the existing areas of damage on the neutral brownish red. Th ere has thus been considerable debate mosaic surface; and (2) the grouting process involves consid- about the most appropriate treatment method2 for the consoli- erable activity on the mosaic surface, as holes have to be bored dation of the mosaics and the possibility of taking any action and the grout almost invariably emerges onto the mosaic sur- regarding the neutral plaster. Th ese two parts of the problem face. Th e leaks are stopped up with clay, which presents an are physically interlinked, for any intervention that globally additional problem with regard to the cleaning and presenta- addresses one necessarily aff ects the other. tion of the mosaic. It was thus decided not to use grouting, but In a bureaucratic approach, this information would the following work was carried out. have been suffi cient for the mosaics to be subjected to a new conservation intervention. However, the mosaics’ condi- • A small number of Plexiglas anchor rivets were tion—with only limited and slight detachment, grime, and inserted to improve the stability of the mortar bed fi ne cracking—did not justify another immediate in-depth on the masonry. This method had first been used retreatment. Furthermore, the brownish red areas are quite in Thessaloniki to consolidate the mosaics in the extensive and have, in the course of half a century, become an TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) 59 TJ14-3 P007-066 200L CTP.indd 59 21/3/08 09:38:08 Black

60 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

during the 1952 intervention was replaced with lime plaster of the same shade. • Great attention was devoted to re-adhering individual detached tesserae, which frequently came away at a touch owing to the network of fi ne cracks and the tiny crevices in the setting bed beneath them as well as the weakening of their adhesion to it. Detachment and loss of individual tesserae has always been a problem, for the lime plaster that covered the mosaics during the Ottoman period has been found in blemishes caused by loss of individual tesserae. Furthermore, a comparative study of the mosaics’ present condition and photographs taken aft er the 1952 restoration confi rms that detachment of the tesserae is a chronic rather than a new or occasional problem. Th e detached tesserae were affi xed to their own imprints in the setting bed with Primal® (40 percent v/v in water).

Removal of Grime and Other Deposits from the Mosaic Surface Th e mosaic surface was cleaned of its heavy layer of grime and soot by the simple expedient of removing the varnish applied during the 1952 restoration (fi gs. 3, 5). Th e varnish was a thickly laid mixture of wax and caseine, which had absorbed the soot and grime, preventing both from penetrating the interstices. It was solubilized with acetone, applied with soft brushes and, as soon as the varnish had dissolved, removed with a sponge FIGURE 4 Stabilization of the mortar bedding on the masonry soaked in deionized water. Th e clean surface was then immedi- with Plexiglas anchor rivets. Photo by C. Bakirtzis. ately dried with an absorbent cloth. Th e removal of the varnish revealed the bright, vivid colors of the tesserae without the need to use large quantities of water or mild chemicals to clean the east barrel vault in the Church of Hagia Sophia mosaic (fi g. 6). No cleaning was done where white stone and TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) (Kanonides and Mastora 2003: 408–9). In the case colorless glass tesserae were observed to have been painted with of the dome mosaics in the Church of the Holy green color in the background of the representations of single Apostles, the anchor rivets were inserted around the saints at the west end of the naos, so as not to remove this inter- figures into the neutral plaster and into the underly- esting structural fi nishing feature of the mosaics. ing mortar bed (fig. 4). In the dodekaorton scenes, Superfi cial mechanical cleaning was carried out using a scal- which survive more extensively, the rivets were pel and dentistry tools to remove, mainly from the surface of the inserted primarily into existing areas of damage of tesserae, remnants of the plaster applied in the Ottoman period the mosaic surface. that had not been completely removed in 1952, as well as other • In very small areas of the mosaic, where the setting plaster remnants that had covered the mosaic surface when major bed was badly destabilized and the mosaic surface and minor damage was restored in 1952. Very little pressure was detached, grouting was carried out with Primal® applied in removing the foreign materials from the interstices for acrylic emulsion (40 percent v/v in water). fear of detaching even more individual tesserae. Aft er cleaning, the • To fi x the tesserae surrounding the damaged areas mosaic surface was fi nely sprayed with a colorless matt solution more securely, the decayed neutral plaster applied (Paraloid® B72, 2–4 percent v/v in acetone), not to enhance the lus-

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The Wall Mosaics in the Church of the Holy Apostles 61

FIGURE 5 Th e Resurrection aft er cleaning. Photo by C. Bakirtzis. FIGURE 6 Detail of the prophet Elias during cleaning. Photo by C. Bakirtzis.

rials (fi g. 7). Th ese mitigated the undiff erentiated appearance of the void and enhanced its neutrality (fi g. 8). Cracks and blemishes in the plaster were selectively fi lled in with plaster of the same shade. No other improvements were made (such as renewing the color or attending to the network of fi ne cracks) so as not to cursorily conceal the associated problems and so that the plaster too would show the eff ects of time, which, in its mute monotony, serves the superb art of the Holy Apostles mosaics.

Current Maintenance Plan Th e current maintenance plan includes the following:

• ensuring the appropriate conditions for the proper main- FIGURE 7 Trial cleaning of the neutral plaster (dome, prophet Isaiah). tenance of the mosaics: monitoring of temperature and Photo by C. Bakirtzis. humidity, regular ventilation of the monument, control of watertightness of roofs and windows, and protection ter of the mosaic surface—which is not necessary—but to protect of mosaics from exposure to artifi cial light; and the mosaics from deposits, based on lessons learned from 1952. • reinspecting the condition of the mosaics’ maintenance at regular intervals, on the basis of the detailed docu- “Neutral” Plaster mentation of both the mosaics’ and the neutral plaster’s Th e appearance of the plaster was improved by dry and wet condition compiled during the recent maintenance cleaning, which removed the deposits of grime and soot and treatments; such inspections will consist of the fre- revealed faint shadows corresponding to the underlying mate- quent monitoring of the reattached tesserae by touch. TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 61 TJ14-3 P007-066 200L CTP.indd 61 3/3/08 11:23:45 AAMM Black

62 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

• Because individual tesserae had become detached, the stability of the tesserae needs to be monitored by touch at regular intervals. • It was ascertained that covering the mosaic surface with varnish has a protective eff ect, as it col- lects grime and soot, preventing them from settling directly on the surface and making it possible to clean easily without mechanical or chemical means.

On completion of the work the mosaics’ appearance was greatly improved without being dramatically changed, and their attachment to the masonry was strengthened. Furthermore, the new panes of absorbent, honey-colored glass that were fitted in the existing window frames in the dome and in the tympana of the arms of the cross have enhanced the spiritual aspect of this superb Byzantine church and show that where mosaics are concerned there is no sub- stitute for natural light.

Notes

1 Stavros Baltoyannis, a colleague of Fotis Zachariou, informed us that the varnish was a secret recipe devised by Zachariou himself, though he believes it was a mixture of wax and casein.

2 We want to thank Francesca Piqué, formerly of the GCI, for defi ning the term treatment in English. It must be pointed out, however, that the English term does not encompass the constant maintenance that mosaics in Greece receive from the FIGURE 8 Detail of the Dormition of the Virgin aft er mainte- Archaeological Service in accordance with the letter and the spirit nance treatment of the mosaic and the neutral plaster. Photo by of the Archaeological Law (No. 3028/2002). C. Bakirtzis.

Conclusion References TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) Th e knowledge gained from the recent maintenance treatment Ardovino, A. M. 2005. Il caso del mosaico di Alessandro di of the Holy Apostles mosaics may be summed up as follows: Pompei: Sguadro sull’ideologia selettiva della conservazione nell’ Ottocento, e rifl essioni per il restauro di mosaici già restaurati. In 8o Synedrio Diethnous Epitropes gia te Synterese • Th e large-scale interventions performed in the past, ton Psephidoton (ICCM): Entoichia kai epidapedia psephidota: which were acceptable at that time in the framework Synterese, diaterese, parousiase: Th essalonike, 29 Oktovriou–3 of total consolidation and restoration, ensured the Noemvriou 2002: Praktika = VIIIth Conference of the Inter- mosaics’ stability. However, they created a situation national Committee for the Conservation of Mosaics (ICCM): Wall and Floor Mosaics: Conservation, Maintenance, Presentation, that constrained subsequent interventions while also Th essaloniki, 29 October–3 November 2002: Proceedings, ed. aff ecting the mosaics’ aesthetic appearance. Any new Ch. Bakirtzis, 63–72. Th essaloniki: European Center of Byzantine intervention must fi rst address the problems of the and Post-Byzantine Monuments. earlier conservation, and it is thus clear that there are Demetriades, V. 1985. Toπογραφία της Θεσσαλονίκης κατά την no total, defi nitive solutions for conserving and main- εποχή της Tουρκοκρατίας. Th essaloniki. taining mosaics (Russell 2004: 35).

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The Wall Mosaics in the Church of the Holy Apostles 63

Diehl, C., M. Tourneau, and H. Saladin. 1918. Les monuments (ICCM): Wall and Floor Mosaics: Conservation, Maintenance, chrétiens de Salonique. Paris: E. Leroux. Presentation, Th essaloniki, 29 October–3 November 2002, ed. Ch. Bakirtzis, 101–9. Th essaloniki: European Center of Byzantine Kanonides, I. O., and P. Mastora. 2003. Preservation of the mosaics at and Post-Byzantine Monuments. the Rotunda of Agios Georgios, the basilica of Agios Demetrios and the church of Agia Sofi a, Th essaloniki, 1997–1999. In Nikonanos, N. 1986. Oι Άγιοι Aπόστολοι Θεσσαλονίκης. Les mosaïques: conserver pour présenter? VIIème Conférence Th essaloniki. du Comité international pour la conservation des mosaïques, Rautman, M. L. 1984. Th e Church of the Holy Apostles in 22–28 novembre 1999, Musée de l’Arles antique, Arles, Musée Th essaloniki. Ph.D. dissertation, Indiana University. archéologique de Saint-Romain-en-Gal: Actes = Mosaics, Conserve to Display? VIIth Conference of the International Committee for Russell, J. 2004. Maintenance: How to protect your place of worship. the Conservation of Mosaics: Proceedings, ed. P. Blanc, 403–13. English Heritage Conservation Bulletin, no. 46: 35. Arles: Musée de l’Arles et de la Provence antiques. Xyngopoulos, A. 1932. Tα ψηφιδωτά των Aγίων Aποστόλων εν Kuniholm, P. I., and C. L. Striker. 1990. Dendrochronology and Θεσσαλονίκη, Arhaiologike ephemeris. Athens. the architectural history of the Church of the Holy Apostles in . 1953a. Ψηφιδωτή διακόσμησις του ναού των Aγίων Th essaloniki. Architectura 20 (1): 1–26. Aποστόλων Θεσσαλονίκης. Th essaloniki. Maguire, H., and A. Terry. 2005. Th e wall mosaics in the cathedral . 1953b. Mονή των Aγίων Aποστόλων ή της Θεοτόκου. In at Porec: Issues of restoration. In 8o Synedrio Diethnous Epitropes Προσφορά εις Στίλπωνα Kυριακίδην. Th essaloniki. gia te Synterese ton Psephidoton (ICCM): Entoichia kai epidapedia psephidota: Synterese, diaterese, parousiase: Th essalonike, 29 Oktovriou–3 Noemvriou 2002: Praktika = VIIIth Conference of the International Committee for the Conservation of Mosaics TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) 63 TJ14-3 P007-066 200L CTP.indd 63 21/3/08 09:38:15 Black

Discussion—Session 1: Evaluating Mosaic Practice

Président/Chair: Demetrios Michaelides

Discussion following Martha Demas into individual hands. We can track our own publications Presentation and know how many copies are sold, but we don’t really know where they’re going. nicholas stanley-price: I would fi rst like to thank all the speakers this morning for an exceptionally interesting series francesca piqué: Th at’s a very interesting question, and I of talks. I have some comments and then questions in terms must say that the searches we did were not aimed at determin- of the Orpheus project, and I thank Martha Demas very much ing dissemination of information. But, just a comment, we felt for a wonderfully self-critical account of the project. A com- that the fact that you could retrieve online so many records is ment when talking about the cost of conservation: hidden in an incredible improvement in disseminating information, and the appendixes of the Orpheus report are the costs at least of it’s also extremely helpful to have keywords and abstracts in the equipment and materials, which were included especially these reference collections. On the other hand, once you deter- because the rolling technique was likely to raise some ques- mine the reference that’s interesting, and you want to look at it tions about costs involved. My question concerns dissemina- in detail, it’s not easy to fi nd. For instance, I was trying to fi nd tion of information. Th e dissemination of all this work that ICCM publications in Florence. Th ese were available only at we do and publish through the papers of this committee and the Opifi cio delle Pietre Dure library, which, because of lack of through other means—and this also concerns the other paper personnel, cannot provide public access. So I had to travel to by Francesca Piqué—how do we know how well this will be Rome to ICCROM’s library for these. Just as an example, then, distributed? For instance, if you search for literature, or in even in a country like Italy, it was rather diffi cult to fi nd some

TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) library catalogs around the world, are you able to get some of the most basic literature. idea as to whether these publications reach, on the one hand, the large libraries of the world, universities, and, on the other, amr nawar al muayyad al-azm: I’d like to thank Martha for the large international citation databases? a wonderful presentation. I have a query. I noticed that you used Aerolam® to place the mosaic on, and considering its cost, martha demas: As you know, there are many ways of search- what was the reason for that? I can see it used in a museum, ing to discover the answer to that question. We did in fact look but I was a bit surprised, considering the mosaic would be put at where the Orpheus publication was in libraries around the back in its place anyway, laid on a concrete surface. Why not world and found that it was in very few of them. We also did just use an isolating layer and unroll the mosaic on it? literature and citation searches that show you where the book is being cited and how oft en it’s being cited. And that was the martha demas: Th e reason for the use of Aerolam® was that basis on which we judged whether it had some sort of impact it would be a good isolating barrier, it was lightweight, and it within the conservation literature. As I mentioned, it was very would allow the mosaic to be lift ed, as you saw, with the crane. poor. So, at one level, it seems like the publication is not get- Th e whole project was expensive; it wasn’t just the Aerolam® ting into libraries. Obviously, we cannot track what is getting panel. I think they saw it as the best way to isolate the mosaic

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Discussion 65

and also make it portable so that it could be transported back General Discussion and relaid in situ. hassan limane: Ce n’est pas une question mais plutôt une patrick blanc: Oui, je voulais juste avoir une précision sur invitation à une réfl exion à travers deux exemples qui nous le problème de l’entretien. Est-ce que vous avez pu défi nir ont été présentés ce matin, et surtout en ce qui concerne pourquoi l’entretien n’a pas fonctionné après votre interven- les couvertures des espaces mosaïqués. Nous avons vu deux tion? Parce que c’est un problème très important que l’on exemples, celui d’une toiture légère qui n’a pas été maintenue rencontre tous. et celui d’une toiture solide, l’exemple d’Alexandrie. Ce sont deux cas isolés, c’est intéressant. Il est tentant de couvrir les martha demas: Th is is probably a better question for mosaïques parce que ça contribue au travail du restaurateur Demetrios, but I’ll give it a try. I think it didn’t take place et ça permet de donner une certaine durée à la conservation, for a number of reasons. One is that this mosaic was situated mais lorsqu’on a l’espace d’une ville toute entière, avec à peu in a gray zone—it wasn’t quite open to the public, but it was près soixante ou soixante-dix mosaïques, la couverture ne accessible to the public—and so it didn’t get the same level of pose-t-elle pas un problème et quels choix doit-on faire ? maintenance as the rest of the site. I think it was also due to the fact that nobody was given the particular responsibility to jarosław dobrowolski: I guess the question is for me. I maintain and monitor the site on a regular basis. And that goes think it’s a question of the general presentation program for back to my point about eff ective management. Th e manage- the site. We have a huge site at Alexandria, and mosaics are just ment structure was really not there to make these things hap- a part of what is to be seen there. I have to be specifi c about our pen, and that’s the reason they didn’t. contribution to this whole proposal. I think it was a very valuable and viable project because it enriched the presentation of demetrios michaelides: I am the person responsible, the site as a whole with a completely new component, with a so I will also answer the question. Maintenance is one of modern component. But preservation of certain mosaics on a the weakest points of the Department of Antiquities. The much larger scale on-site was not to be considered. Th is site is Orpheus mosaic and shelter are not the only victims, just a concession of the Polish Center, and it is responsible for the very obvious because the structure is separate from the rest. overall problem of conservation, together with the Supreme Also, we have to bear in mind that the shelter was built to Council of Antiquities. So, yes, this project was, in a sense, be temporary, with a life span of three or four years, and isolated, but it was never meant to be anything else. replaced by a permanent shelter. This was in the 1980s; we are now in 2005, and it’s still a temporary shelter that is wait- denis weidmann: Le problème avec les abris, sans entrer ing to be replaced and that is not maintained. All the same, dans le débat général sur les abris qui sera, je pense, ouvert it’s not an excuse; it should have been replaced because it is ces prochains jours, est qu’il faut trouver ici une limite de la becoming a safety matter. gestion de l’abri lui-même. Nous avons vu à Paphos, un abri léger c’est une illusion, du moins pour quelques années. Dans aïcha ben abed: Dans le cas de la mosaïque d’Orphée, consi- nos climats du Nord des Alpes, les abris peuvent être lourds, dérant l’eff ort et le coût qui, si mes souvenirs sont bons, furent c’est de la construction traditionnelle, mais la limite est plu- très élevés pour cette opération, sachant qu’il n’y avait pas tôt trouvée dans la possibilité future de gérer et d’entretenir de suivi, qu’il n’y allait pas avoir d’entretien et de véritable ses propres abris. L’abri ne doit également pas devenir une gestion de la mise en valeur de cette mosaïque et de la dépose, machine à détruire la mosaïque, c’est un phénomène que l’on pensez-vous que cela valait la peine de faire ce projet ? trouve très souvent. On part d’une bonne intention, mais après, par eff et architectural, par eff et constructif ou par eff et martha demas: One of my main conclusions is that we were de pollution, on s’aperçoit que l’on a accéléré la destruction. not really thinking in that direction. It was an intervention C’est plutôt une question de collaboration entre les architec- to resolve a particular problem of the mosaic, one mosaic, tes et les conservateurs. and we were not thinking holistically. Th e project wasn’t con- ceived holistically. And on the other side of it, there was not federico guidobaldi: Th is is a question that can be directed to a vision by [site] management to think holistically either, so more than one of this morning’s speakers. When I see a mosaic the groundwork wasn’t there for it to have been an eff ective, before the dépose, I don’t directly see the reasons for removing integrated outcome. it. When we see the Orpheus mosaic for the fi rst time in its TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S) EX Gold East M/A 115g 200L X H:11” TJ14-3-2008 PO(Sam) GCI W:9” 65 TJ14-3 P007-066 200L CTP.indd 65 3/3/08 11:23:50 AM Black

66 Lessons Learned: Refl ecting on the Th eory and Practice of Mosaic Conservation

original situation, or other mosaics for which the archaeological vation.” So maintenance does not have a specifi c Greek trans- context and what exists below remain, and how lift ing destroys lation. Anyway, we use maintenance to speak about repairs, to the mosaics, I ask myself if it’s not better to leave them in the speak about care. soil. It is important, I think, in the conference recommendations roberto nardi: A simple comment on this paper. Part of it is to advocate in situ conservation and to study the mosaics better, a few small, technical details that I would be interested in dis- because they are not studied very well. cussing in more depth. It was extremely interesting to see an attitude applied that is based on actions implemented accord- Discussion following Charalambos Bakirtzis ing to cautious and careful decisions. Th is is not the result of Presentation technical decisions taken six months ago; this is obviously the result of a long process, a long political process that started francesca piqué: Th e meaning of maintenance is not always years and years ago. I am not involved with this [project], but clear or consistently used by the profession. Could you defi ne I imagine this [was the case], because if we compare similar what you mean by maintenance in Greece? interventions carried out in similar regions, the decisions are charalambos bakirtzis: Maintenance is not a Greek very diff erent. Th is demonstrates the fact that technical deci- term. We used to say, as you’ve seen in the proceedings of sions, even the best technical decisions, need strong political the Th essaloniki congress, that maintenance is translated as support that has to be initiated far in advance. So I was very διατήρησις (diaterese). But this is actually the word for “preser- pleased and impressed by your work. TJ14-3-2008 PO(Sam) GCI W:9” X H:11” 200L 115g EX Gold East M/A Magenta(S)

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